I was baptized when I was 16. Although I had some contact with the missionaries, most of my preparation was through ward leaders and one of my high school teachers.
My parents allowed my baptism, but weren't terribly supportive. I was determined to learn what I needed to know to be completely active in the Church so I kept learning (and making mistakes). I was able to attend BYU which helped me a great deal.
I think that if you are considering joining the Church, the most important thing is that you have a solid testimony of the Gospel, especially of Jesus Christ. After that, things will come along in their own time.
Oh, and, just for the record, this all happened nearly forty years ago. I can remember it so clearly as my baptism was one of the most important turning points of my whole life.