Help! I'm a Sikh and wanna cut my hair!?

Im 17 and i found many discrepancies in the religion so I decided to only follow the first guru. I told my parents about this and they're scared about what others in the sikh community are going to think so they won't let me have one Or let Me get rid of the turban. How to I convince them? And for all you Sikhs that are going to say I'm not a true Sikh or are going to try and stop me, is there any part of your body you don't trim? Do you keep all the 5 k's? Including the kanga and Kirpan of the right length? If you answered no to any of those questions don't try and say I'm not a true Sikh on this question. I have to do what they say because I live with them and they are going to pay for college. What do I do? Every time I bring it up with my dad he just puts it down.