18 might be a bit young to make a surgery/no surgery decision. I had a similar case to you when I was your age and it looked fine, although it did kind of bug me and I wasn't real comfortable taking off my shirt. I knew I looked better than 90% of the pop., but the nips just bothered me. As I rolled into my 30's and had more family/work commitments, the gym was less and less of an option - you just don't have time. As you age, it's tougher and tougher to keep the great physique. By my mid 30's it looked terrible, and I had the surgery recently at 37. Pretty happy with the result, but I kinda wish i had done it at 25 or so because I would have had all that time of it not bugging me + I would bet that the result would be better on a younger body (more resilient). I wouldn't be in a hurry if I were you, but see where your at in a couple of years. If you really want to deal with it surgically then - do it at that time.
It's gland that causes you to have a disportionate amount of fat around your chest. You can only get rid of that fat by getting down to an unreasonable BF% (like less than 5%). But it you keep your regimen, your still going to look good.