Hi Jaguar,
Cutting smoking was the necesssary first step - well done.

Another plus for you is your age - you are young and your body is able to heal and repair itself better than the usual angina sufferers, which are often in their 60s and 70s.
Research has shown that angina, or plaque buildup, responds much better to positive lifestyle changes in younger people. Even children can have plaque in their arteries and they have found that diet and exercise alone can reverse that plaque buildup relatively easily. This is partly because the young arteries, in particular the muscular artery walls, flex much more easily during exercise.
So in addition to ceasing smoking you need to keep up with your exercise.
I would suggest strong exercise where you puff and pant, however because you have a stent and some level of disease, you need to develop your program gradually, and perhaps in consultation with your doctor.
Statistics can be your worst enemy here. Remember they include many people where the disease develops in an undiagnosed state (and then strikes), and many others who CHOOSE to do nothing about the necessary lifestyle changes (either smoking, diet or medication).
Medication is something you must adhere to now as well.
Keep your blood pressure under control (top priority)- exercise will help with that - keep your cholesterol down with medication and diet, and you should live to a fine old age.