I knew a girl that was baptized, disfellowshipped in the same year before she was 18.
It was one of the saddest things I had ever seen. She was abandoned by her family and moved in with this JW family and started studying. She happened to be a classmate of this family's JW daughter. This girl became convinced being a JW was what she wanted and got baptized. Not long after baptism, she got pregnant, disfellowshipped, and the JW family kicked her out of their home. I never heard what happened to her, but that is about the saddest thing I'd ever heard of.
In a twist of events, the ordeal stuck in the craw of the young JW daughter because her Elder dad had been so cruel to her friend. About 2 years later she also left the JWs, I don't remember if she dissassociated or was disfellowshipped. I just know when I asked whatever happened to her, I was told by her uncle that, "We don't talk to her anymore." That would make the JW daughter 17 when she was baptized and out by the age of 20.