(I don't own this picture. All Rights go to the owners.)

Name: Brianna 23

Gender: Female

Age: Teenager 

Appearance: Has long blue hair in low pigtails with light brown hairstreaks and wears a white long sleeve shirt underneath a light blue overall dress, black tights, royal blue mary jane strap shoes, a mint green headband, an emerald green zip-up hoodie, light blue and pink striped armwarmers, a mint green satchel and a light blue crystal pendant.

Family: Ben 23 (Adoptive Brother), Max (Adoptive Grandfather/Deceased)

Others: Second Wielder of the Omnitrix.

Sounds like Stefanie Scott