Blaine is a college student and Kurt is in McKinley. There is only about a 1 year age difference.
The New Directions don't know that they've been dating for 3 months. Blaine has been invited to come to McKinley's glee club and demonstrate the things they do at NYADA.
-_-_-

"So, today I have invited a NYADA college student to come in and demonstrate some things that they do there, for any of you budding NYADA students." Mr. Schue looked pointedly and Rachel and Kurt.

"Ooh! This should be amazing! Don't you think, Kurt..? Kurt, why don't you look excited?" Rachel practically shouted next to Kurt.

"I am excited but I can't exactly show it when I have a badly dressed brunette screaming down my ear." Kurt glared at his best friend.

"Okay..." Mr. Schue frowned at Kurt, "He should be arriving soo-" there was a knock at the door signalling the NYADA student's presence, "Now!"

A raven-haired boy strolled into the choir room and Kurt's jaw almost hit the floor.

"Hi! I'm Blaine Anderson and I..." Blaine trailed off as he saw Kurt staring at him with wide eyes and a gaping mouth, "Is there a problem, Mr. Hummel?" Blaine chuckled as Kurt shook his head and glared at the hazel eyed boy.

"Nope. Not at all, Mr. Anderson." Kurt dragged out the last syllable of 'Anderson' which he knew would affect Blaine.

"Right," Blaine coughed awkwardly while trying to hide his blush and Kurt simply smirked at the struggling boy in front of the New Directions, "Well, uh, I was th-"

"Are you alright, Blaine?" Mr. Schue interrupted the boy and patted him on the back.

"Perfectly fine." Blaine smiled but as Mr. Schue walked away Blaine turned to glare at Kurt who simply stuck his tongue out in return.

Kurt giggled when Blaine mouthed the word 'Immature' which caused Blaine to roll his eyes, even though he was smiling because that was one of the most adorable sounds Blaine had heard.

"Are you going to teach us anything?" Rachel raised a hand while the other New Directions just frowned and glanced between the two boys who were yet to break eye-contact.

"What? Oh... Oh yeah. Right!" Blaine grinned and practically skipped towards the piano.

"So, this is just a little taster of what we do." Blaine rested his fingers over the keys, "This is one I wrote myself. It's called 'Not Alone'."

"Oh my goodness! You write songs? I write songs too!" Rachel clapped her hands.

"That's... Cool... But I was planning on, oh I don't know, actually playing the song." Kurt smirked at Rachel whose face immediately dropped as she stared at the hazel eyed boy playing the opening chords to his song.

I've been alone
Surrounded by darkness
I've seen how heartless
The world can be

Blaine closed his eyes, a small smile gracing his lips as he imagined the blue eyed boy that inspired this song.

I've seen you crying
You felt like it's hopeless
I'll always do my best
To make you see

Kurt tilted his head at his boyfriend who looked so at home performing.

Baby, you're not alone
'Cause you're here with me
And nothing's ever gonna bring us down
'Cause nothing can keep me from lovin' you
And you know it's true
It don't matter what'll come to be
Our love is all we need to make it through...

Blaine slowly opened his eyes as realisation hit him; he could actually look at those beautiful blue globes this time.

Now I know it ain't easy
But it ain't hard trying
Everytime I see you smiling
And I feel you so close to me...
And you tell me;

Finn frowned at his girlfriend who was staring dreamily at the piano-playing boy at the front of the choir room.

Baby, you're not alone
'Cause you're here with me
And nothing's ever gonna bring us down
'Cause nothing can keep me from lovin' you
And you know it's true
It don't matter what'll come to be
Our love is all we need to make it through...

Blaine glanced down at his keys every now and then to make sure he was playing the right chords, even though his fingers slipped into autopilot every time he performed this song. It was based on his true love, of course it was his most played song.

I still have trouble
I trip and stumble
Trying to make sense of things sometimes...

I look for reasons
But I don't need 'em
All I need is to look in your eyes
And I realize...

Blaine looked straight into Kurt's eyes, trying to communicate with his boyfriend and tell him that this song was for him.

Baby, I'm not alone
'Cause you're here with me
And nothing's ever gonna take us down
'Cause nothing can keep me from lovin' you
And you know it's true
It don't matter what'll come to be
Our love is all we need to make it through...

Kurt smiled adoringly at the top of Blaine's head as his face was facing the piano keys once again.

Oh, 'cause you're here with me
And nothing's ever gonna bring us down
Cause nothing, nothing, nothing
Can keep me from lovin' you
And you know it's true
It don't matter what'll come to be
You know our love is all we need

Blaine stared back into those ocean blue eyes as he sang the last lines.

Our love is all we need
To make it through...

"Wow! That was-just-just wow!" Mr. Schue laughed and Blaine grinned appreciatively at the choir teacher.

"I write songs too." Rachel said in a barely audible voice.

"I know, you told me before." Blaine frowned at the girl.

"Yeah but, I write songs too." Rachel clasped her hands as she stared at the boy of her dreams.

"And..." Blaine gestured for her to finish his sentence.

"We-it's like we were made for each other." Rachel tilted her head as she continued to stare dreamily at the confused boy at the front.

"I-uh-I'm sorry, what?" Blaine shook his head in confusion.

"He's gay, Rachel." Kurt whispered as he leant into his best friend.

"How do you know that?" Rachel shrieked at her best friend who moved away in alarm and covered his ears. Rachel turned back to the front before asking the boy; "Are you gay?"

"I-uh-yeah, yeah I am." Blaine narrowed his eyes, "I'm really confused, why are we made for each other?"

"She means you're, like, soulmates." Kurt shrugged.

"What? Oh, no!" Blaine laughed, "Don't be silly, Kurt's my soulmate."

Kurt froze and Blaine turned slowly to look at Kurt. "Oops." Blaine muttered as he stared at his boyfriend's frightened face.

"You're dating?" Mercedes whispered loudly.

"No." Blaine squeaked unconvincingly.

"Yes." Kurt said more confidently and Blaine turned to Kurt, "What?"

"You-I-I thought you didn't want anyone to know." Blaine gulped.

"I thought you didn't want anyone to know." Kurt rolled his eyes.

"Oh." Blaine pursed his lips, "Well, I definitely didn't wanna hide you, I just thought you didn't want anyone to know."

"Why wouldn't I want anyone to know?" Kurt frowned.

"B-because I'm your first boyfriend." Blaine shrugged unconvincingly.

"I'm your first boyfriend as well." Kurt pointed out, "What's the real reason, Blaine?"

"I thought you weren't ready because of that whole Karofsky thing." Blaine ducked his head in embarrassment.

"Oh. No, honey, I was over that ages ago." Kurt nodded, "Trust me, I wouldn't of dated anyone if I hadn't recovered."

"Oh. We're not very good at this, are we?" Blaine chuckled.

"No. Not really, but we're not very experienced either. We'll learn together." Kurt laughed.

"Well, that was unexpected." Finn coughed awkwardly.

"To say the least." Puck added from beside the jock.

"Sorry, I would've told you girls sooner if I'd known he was okay with it." Kurt looked apologisingly towards Tina, Mercedes and Rachel who were glaring at him.

"Why don't I just do another song." Blaine said awkwardly before moving to pick up a guitar.

The song was 'Not Alone' by the amazing Daren Criss.
I'm going to be starting a chapter fanfic soon instead of just oneshots so I might not update for a while because I need to work on the new one.