Detonate:
You overestimate your abilities, and won't know it until you are challenged beyond what you are comfortable with. You also need to ask whether other people were comfortable with you having a camera on your 10th dive -- you might be surprised by their answers after having watched you. Absolutely no one should have a camera on their 10th dive. Many shouldn't have one on their 100th.
Diving is a mentally demanding activity, and sometimes a physically demanding one as well. Photography is a mentally demanding activity. The combination of the two goes well beyond what any inexperienced diver should subject themselves to. I think 100 dives is the point where people might have the experience needed to judge whether or not they will be comfortable with the extra distractions and task loading. Taking pictures will unquestionably decrease your diving skills. You need to be at a very high level to start with to afford such a hit to your attention, skills, physical dexterity, and resistance to panic in adverse conditions.
I've seen too many people destroying reefs, kicking up clouds of silt, colliding with other divers, and just being generally oblivious to their surroundings and gauges to think that anyone but an advanced diver should have a camera. I personally regard myself as an excellent diver without a camera, and an adequate diver with one, and am rather chastened and embarassed by some of the things I have done while taking pictures. But above all it is a matter of safety -- novice divers should be developing their skills and paying attention to their gauges.
