What would you do?
Very hard to say what would I do in that situation.
In no way would I make him feel disrespected. However, there may be a way to let him know that on one hand he's telling you that it's your decision, but on the other he's pressuring you to do what pleases him.
Please understand that in your JW father's mind he's saving you and your life. He believes that by pressuring you to baptize he's pretty much taking you with him to "paradise on Earth". That is no small thing. So whatever you decide to do, the one thing that I suggest you to consider are the feelings behind his actions. His heart as a father is (or may be) in the right place.
Maybe acknowledging that his efforts (though severely misguided) come from a good place may make him listen to you a little more. Something along the lines of "I know that you want to share paradise with me and the rest of the family, and I appreciated that". Then stand your ground a little about this making your decision, and that it will be made 100% once you're sure. Please notice the words. You're not saying you're going to baptized, nor that you're not.
For as long as you depend on your parents, you may need to play that game of dodging this kind of things, including a lot of pressure. Meanwhile, prepare to become as independent from them as possible if you finally decide not to become a JW.
I hope this helps.