I know that getting baptized is a bad decision but I had an incident last year that I really, really don't want to repeat.
While I won't speculate what the incident was, what makes you think it won't be repeated after you are baptized? If it was repeated after baptism, if caught, it would likely result in more extreme 'punishment' by not only your parents but also by every JW on the planet.
I would suggest discussing with your parents that as Jehovah only wants followers that do so willingly out of love and desire to please him, would it be acceptable to Jehovah if you were forced into baptism due to their constant pressure and threats of punishment?
As baptism is a lifelong promise and commitment to God, how is it that you are mature enough to make that commitment when you aren't legally old enough to commit to another person, or to drink alcohol?
Your parents likely don't even permit you to decide how late to stay out or what clothes or hair style you can wear.