How can i convince my parents (Need help pleasee)?

hi i am 15 and Indian from a Sikh religion and i have a turban and i dont want it any more, how can i convince my parents to get a haircut, if i dont cut my hair this summer i probably wont get a haircut ever in my life. im scared my parents might get mad or might not let me but i really got to do this i have a 2 month period to convince them!