Name: Princess Starshine Crystal, but her sister calls her Star, or, when she wants to annoy her, Shi-shi.

The name is very very mary sue-ish because of Star in there. So that's a -5, I won't put it big because everyone has trouble naming mlp. If you need any help naming an oc I'll help you.

Age: 13

Then with a young age is understandable, but fillies and colts get there cutie marks at the age 8-10. So -15 because that is a big part in the mlp fandom. I get that you have an idea of one but you need to know because she is past the age.

Race: Alicorn

The fact this it's a alicorn is a -10 of the already 100.

Relationships: She doesn't have any friends, besides a handful of crystal ponies she nods in passing. This isn't because no one likes her, but the fact that Starshine is simply a very private pony. Besides that, there is Princess Cadence (Mother), Shining Armor (father), and Princess Flurry Heart (sister).

Her family being one of the canon characters are -8.

Appearance: Coat is relatively dark shade of purplish pink. Mane is in wavy clumps of very light and dull pink and lavender. Blue eyes, bark blue, small framed, rounded glasses.

The dark colours also go to the emo side so -5 besides her mane with is a great mane colour. If it wasn't an alicorn the man and coat will be fine anyway.
Cutie mark: Currently, she's a blank flank, but I have a vague idea of what I want it to be.

Personality: She's an introvert, preferring to seek her own company rather than that of others. She delves herself into her studies in order to discover what kind of magic she excels in, and is therefore princess of. Whenever she is required to attend a formal event, she plasters on a half-smile and tries to get out of there as soon as possible. Star holds fierce determination and perseverance, but she is rather close-minded. She has a habit of viewing others with contempt, generally reserved for those she believes are naive, or simple. However, she is surprisingly loyal, especially when Flurry Heart is involved. After all, she is her best friend, and, much as she denies it, she isn't sure what she's do without her.

The personality is wonderful slightly but you can change by adding some flaws in there.

Backstory: When Starshine was born, her wings weren't like that of a normal alicorn, or even that of a pegasus. They were incredibly small, and it became evident that she would never be able to fly. Still, Cadence and Shining promised to love her the same as Flurry Heart, who already had flight skills akin to that that of a normal adult pegasus. Star's disability bothered her when she was younger, but she's come to accept it, and now it barely even crosses her mind. Sheltered in the castle for much of her young life, she didn't venture out much unless forced to, and even then, she pretty much ignored all the other fillies. She idolized her sister and mother when she was younger, like all well-brought-up small children do, until her views branched off from theirs. At that point, Star began to disregard the two, which morphed into disrespect bordering on rude. Eventually, she would tell anyone who would listen that, "I want to become like Celestia and Luna. Their work has real meaning, unlike Cadence and Twilight. I mean, how much power can something as abstract and debatable as love and friendship possibly hold any power? It's just propaganda to disguise the fact that they aren't actually doing anything. Seriously, when was the last time you saw my mom doing work?" Word of this eventually reached Cadence, and in response, she sent Starshine (Along with Flurry Heart, who begged) to Ponyville and the Mane Six to learn about friendship and its importance.

Giving her the lonely background and how she doesn't have alot of friends gives to the emo side so -5. The share small wing weakness is like scootaloo which shows that some other ponies can have what she has which is good. The slightly sad background is anotger Mary sue trait which takes -10. Your oc may need alot of work but it can be an awesome oc if you just fix a few things that I added in.

Okay so you get a 42/F you are a Mary Sue.