Everyone has them so any guy that makes a big deal about them is just plain dumb imo. As long as YOU aren't making a big deal about them or trying to hide them all the time, I'm sure they won't care or it's likely they won't even notice...so don't worry about it.(:
i have stretch marks, most people do, including guys, and really anyone who doesn't except you for you is not worth being with. You are young and when you are old you will look back at how beautiful you were.