I wholeheartedly disagree with those saying that you should study with your dad and challenge him if he has anger issues. When something is unhealthy, you don't double down on it and hope that it somehow changes, you get out of it. You can't just leave, but I would do whatever I could to NOT study with him. You aren't going to change his mind, you will only piss him off because he wants to control you, thus the pressure. Find ways to delay or get out of it. You have quite a history on here and we've chatted in pm's, so you know that giving in and getting baptized isn't a great move either. It must be hard to be isolated and under constant pressure. I don't remember how old you would be now, but you as you get closer to old enough to move out he may ramp up the pressure. Your deliverance is near though. Don't give up as you get closer to freedom.
If a person can get you to take one step with them, it is much easier to get you to take a second, and a third, etc. It is sales. If a door to door salesman can get you to stand there and talk to them, they're laying groundwork for a sale and people will buy when they though they'd never do such a thing. If you take this study, you're taking that first step. Beware. In the end, it's your life, and none of us know all of the circumstances, so we can't tell you what to do, but we can give you our opinions, and this is mine.