Im 14 years old and I'm going to turn 15 next month. I have an 8 year old brother. I live with my dad. I get to see my mom every other weekend. My parents were separated for about 2 years and then divorced last year. My mom tried to win me and my brother back but she still hasn't. I don't want to like with my dad anymore because he's... not so nice. My mom doesn't know what else to do. My mom said if she can't do anything else than I'll just have to wait till I'm 18.

Your mom has to file in Family court for a change in custody. The judge will listen to your preference, but will make their decision based on what the court thinks is in your best interests.

Why did dad get custody in the first place? That is a bit unusual.

If it was court ordered then there has to be a reason that your dad got custody because as scott pointed out that is somewhat unusual, not unheard of but not the way the majority of cases go. Your mom would have to file in family court (the one that awarded your dad custody) for custody. She would have to show the judge enough evidence that your and your brothers would be better off with her. Otherwise yes you will have to wait until you are 18.