I started smoking when I was 13 as well. But started smoking heavily (more than 1 pack a day) in 1993. Quit when I was 20 years old, and started back 7 years later. Now, the longest I can seem to quit for is about 3 months at a time.
I realise however, that if I ever want to enjoy years longer of scuba diving, especially as a Rescue Diver, I should put my own health ahead of others first... because really, how can I care for someone else if I cannot care for myself?