My sister is 19. Does that count as an adult?
im not to sure as i havent been to an abortion clinic before, they may ask for parental consent. Not 100%. But i think going behind everyones back is risky and will hurt alot more people. Maybe you should try talking to someone else, preferably in her family. But if you have run out of options, your sister mite work, maybe try going to the doctors and talking it over with him/her 1st and see if you need a parent with you for the abortion.
If you are over 18, you are considered an adult. But you are still 3 years away from being legal. Meaning legal drinking age.
Technically it's 18, but I don't believe that there's a set age. Different people mature at different rates.