tough. i'm guessing you're under 18? if you are, you need to tell your guardians. if they say no, you also need to respect their wishes.
that being said, wait for the right moment, you need to tell them, but if you don't feel the timing's right, you should wait a bit longer. be calm, and explain everything as best as you can. if they put their foot down, it sucks, but you've got to respect their discussion, sucks, but once you turn 18 you can start right back up.