(http://i.imgur.com/hXjsJtH.png)
I introduce Crayon Spectrum!
how she got her cutie mark is a short story (Kind of)
One month, her family was slowly and slowly getting more and more poor, so Crayon thought she could help.
She tried everthing to raise money ,but nothing worked. Her lemonade was bad, and her bake sale got rained on.
But one faithful day, she found some crayons lying in the classroom floor. She then thought she could make art to help raise money.
She stayed up all night drawing pictures from pure crayon. When she showed her parents they were excited! The pictures were like the Mona Lisaof Equestria. She took them outside made a stand and sold her art for reasonable prices and got enough money to save her family. 0:)
Awwh, ain't that a sweet story ^-^
But, she basically stole the crayons, didn't she..? o.o
Actually, how is she in school in the first place? Since the family's poor.
Also, it's quite unlikely that someone that just got a hold of crayons would suddenly know how to draw extremely well. Even if someone is artistically gifted, I dare say. You could say that she had to practise drawing a little bit before she was able to make real masterpieces.
I think you should probably add that her parents got sacked from work and couldn't find new jobs. That would explain why they weren't able to get more money. Either that or they were in debt.
But that's all just my personal thoughts. It's up to you how to shape your character, really ^-^
Also, sorry if I offended you anywhere in this post X3
Its known as destiny, she was naturally good at birth.