I was born in (3rd generation, even) but managed to hold out until I was 18. My sister was baptized at 11, and confided in me that it was only because a bunch of her friends where doing it at the time. I resolved then that because it was always said to be an important "decision" I wanted to make sure that I only did it because I loved Jehovah. I never had any long-term friendships (inside or out) so I never quite got pressured to get dunked by them, so it wasn't much of an issue. I think after a certain point, people just assumed I was baptized.
The problem was that my father started pressuring me to get baptized before each assembly/convention starting at about 12. I held out for 6 years with one of my major reservations being that I felt unlikely to ever find a girlfriend/wife in the organization (all the girls were just out to get married, and they all seemed shallow and stupid to me, as did many JWs in general). Then I met a girl that wasn't shallow and stupid, we dated for a while (she was my first love) and she broke up with me (probably pressure from her parents) and in my heartbroken state my father one day came into my room apparently with one thing on his mind. We had the following conversation:
Him: Did <ex-gf's name> know you weren't baptized?
Me: I don't know....we never talked about it.
Him: How do you think she would've reacted if she'd found out you weren't baptized after you'd already started dating?
Me: I don't know....
Him: well that's something to think about.
And that did it. I thought I was being punished for not being baptized, and god was dangling a carrot in front of me to get baptized. I actually resented Jehovah for a long time due to "his" tactics to get me to be baptized. It makes me sad to think about now, because it's really the only time that my father betrayed me, and it was such a deep betrayal to take advantage of a heartbroken teen to pressure them to join a cult. I know he had good motives, but it's still hard to forgive him for it.