Try a demi color gloss first. Since you are 12 you will have to have your parents permission if you go to a salon. You could do a nice demi color gloss to deepen the color and add shine or maybe mom will let you experiment with some subtle highlights.

You do have the Cheryl Cole look! You could totally look like her!

Maybe start with some highlights around the front.....a golden blonde or carmel color would suit you and add some brightness.

Because of your age, I would recommend discussing this with your mom first. Ask her, if she will take you to a hair salon. Bring pictures of Cheryl Cole with you, and show the hairdresser exactly what you want. Then I would ask for either a gloss in that color or a semi-permanent hair color. Both of these will rinse out after a month or two. If you don't like it, then you're not stuck with it.

I like your hair that color personally. And since you're only 12, maybe wait for a few years before starting to change the color. ;)

just focus on my skin and eyebrows my hair looks lighter there then it actually is