My son got his JOW at 10 and dove with me in Cozumel that same year. He now has almost 40 dives under his belt (now 13) with almost all in Cozumel. I agree that they have to have the maturity but it also takes an instructor that is really willing to teach. His first instructor was against it and it was difficult. The pool work went very well and I think it surpised him (some other adults had major problems). The class work did not go as well for a couple of reasons. My son's birthday is in February and class started in March. Due to school we tried the 2 weekends schedule instead of 5 evenings. Class was spent on grading the quizzes, watching the videos, then a quick Q/A session which was backwards and not enough time. He missed the test by 2 and we felt like it was kind of a "told ya". We changed shops and it was like night and day. Passed the instructor "feel out" of his knowledge to see if he was totally lost, worked on the parts that the instructor felt he was a little cloudy on, and then passed the test without a problem. Overall my son is a competent diver that DM's don't have a problem diving with (unlike some others on the boats at times).