Is it normal to daydream about someone else?

Man or woman. We both do it. No offense, but this is the equivalent of a woman wagging her pussy in your bf's face and him taking the bait. You don't want to be that person. Write it off as a harmless crush and don't even allow those feelings to manifest. He's given you a little attention and you're feeding off of it. Nip it at the bud.

"I'm kind of worried about myself though, I think that maybe because my relationship is going so well that I might be starting to feel a little trapped or something, and I see this other guy as kind of a path out of growing up if that makes sense? At this point the relationship I'm in will probably lead to marriage if one of us doesn't completely fuck up (which I do not want to happen at all), so maybe my subconscious is freaking out or something?"

I think you just answered your own question, there. This is normal, however, and it's also normal to feel some guilt. I'd even say healthy. We have this huge obsession with feeling good all the time about everything we do, but that's not healthy. Your feelings of guilt show that you respect your boyfriend and acknowledge the commitment you've made to him so far.

I wouldn't obsess over it, but I would try to combat these fantasies and push them away. They won't lead to anything good, and the fact that you feel guilty about them means that any pleasure you get from them is already tainted and mixed with discomfort.

Fantasizing about other men is normal and it does not make you a worse person for it.

The only problem with fantasizing is that it increases the likelihood of you acting on your fantasies and in sense, can lead you on a path towards justifying any sort of unfaithful behavior.

I would recommend you not hang out with this dude that you have a crush on. Better safe than cheating.

Don't tell your boyfriend.