Why wont my hair stay straight?

so i want to re-scene my hair... In 6th grade, i had really scene hair. were it swooped over to the right and covered my right eye but left my left eye in plain sight. I wanna re-do this. But after 2 years, (8th, going into 9th) my hair wont stay straight anymore, everytime i curl it, it just goes back up into my curl. On the right side my hair curls up and has a wing. I just got it cut, and it doesnt have the wing anymore if that helps. But i was just wondering what i should do... ooh and my hair is really thick when it re-grows in anymore. in 6th it grew down, not up like it does.