I've been the first for a handful of guys. My favorite was a guy who never had a blowjob at all. It was just going to be a wank session, but I can't be in a room with a hard cock and not have it in my mouth. He moaned loudly the entire time and came so hard I thought he was going to pass out. He kept looking at my cock, and I asked him if he wanted to try it. And, he did! Decent blowjob and took my orgasm like a pro. I'm happy to report that I turned him into an avid cocksucker.
They do say that men make the best cock suckers as we know what works best, as we know how it feels to be sucked. If you are already thinking about it, you will eventually just go for it and try it. Curiosity will get the better of you, and why not. Nothing wrong with pleasure between consenting adults. You can try it once and see how you like it. If you try it and you just cant enjoy it as its a man sucking you off, you don't need to do it again. However if you find like most of us that, a mouth is a mouth and it feels great. Then enjoy.