I'm 17 and I can happily say that if I was EVER in that situation I'd either a) Discuss it through, or b) Face up to the consequences. It's cowardly not to, so her age can't be blamed for that.
She needs to get over herself. If anyone does anything against her, she takes an instant dislike to them...

I dislike Grace predmoninantly because she takes herself FAR too seriously.
Oh yeah and now Nikki knows that Pete likes her... she's not gonna let him go.