In America, so long as you have insurance, birth control pills are now free. Some states allow minors 12 and up to go to doctors alone. Check your state laws and/or check with your local Planned Parenthood.
It can sometimes be tricky without your parents' consent, at age 17. I would look up your nearest Planned Parenthood and see what they say. In the meantime, use condoms with contraceptive foam.