Long term effects of smoking 1 year in your very early 20's. Serious? No Worries. Glad you stopped. Take care of yourself and you should be fine. Lung Cancer is a crap shoot anyway. Chris Reeves' wife died of it and never smoked. Some folks smoke there whole life and no problem. Your biggest problem with smoking that goes unspoken of usually is COPD, and its a serious problem. Good Job for quitting. You will be better off for it.
There are elderly people in there 70's who have smoked their whole lives and are still smoking. You're fine.