After looking at that picture crab, I don't think you will have to worry about man boobs.
You are young and experimenting and having fun, just don't go overboard. Most of us older folks did it too though I never worked out then and I drank every Friday and Saturday from 16 years old to my early 30's. I never drank beer as I can't stand it but again, I never worked out or did martial arts. I was 27 when I started weight lifting and still drank on the weekends though as my weight lifting got more intense the less I drank. Now it is the occasional time as drinking doesn't hold the same pleasure it did and I can have just as much fun and be as silly as I was then without it. I do enjoy the occasional night with the friends and there are times out where you have a couple and would like to spend the rest of the night drinking but there are other priorities.
Just play it safe and be sensible about it. If you want to lead a healthy life and still include drinking in this then you will have to do it in moderation and again be sensible. Don' work out and then go drinking. Don't drink and then workout. If you have a hangover of any degree then don't workout. I think you will find like myself that these types of issues where I couldn't work out I felt guilty about not working out and that took more priority in my life. I don't always enjoy working out and hate it some times but I hate it more when I can't.
Have fun being young, you are only young once. But don't waste your youth.