Hey Pandas, I Need Y'all's Advice.

This is a throwaway because some people I know are on this site, and I don't want them to get involved because it doesn't concern them but they would be nosy.

Anyways, I have been dating this girl (let's call her Lynn) for almost a year (June 1st is our anniversary because gay) and I have had concerns about our relationship before (my ex and I were much more romantic and less platonic, and her and I act like an old married couple) but I can see myself with her in the long term.

The problem is, I'm still fairly young, since I'm in my first year of high school. I'd always had the concern in the back of my head that even though I was sure I loved Lynn, I wasn't fully okay with giving up the whole teenage/early 20s dating life. I was also (still kinda am) a little worried that since we would mature and change, we wouldn't be as romantically inclined, and it would become two roommates as we got older, but we've known each other since we were little kids so that might not be as much of an issue.

Here's the thing: Earlier tonight someone confessed to me (let's call him John) and our situation is a little complicated. We've been in orchestra together for three years now,and grown fairly close, but after I broke up with my ex last March, I started to get a suspicion that he might like me. Soon after that I started dating Lynn however, so it slipped my mind, especially since we didn't see each other over the summer. I just put it down as my tendency to over-think things, romanticize everything, or my lack of normal relationships with guys.

However, as previously mentioned, he did like me. We were sitting in the audience after performing for a judge/doing a "concert" and during a pause, he leaned over and whispered "Do what you want with this information, but I kinda like you."

I just sat there for a good five minutes, processing. I know that I should have told him about Lynn immediately, but if I'm being completely honest, I like him too (and my mother agrees that we like each other, I told her about this because I have no clue what to do) and if he had confessed earlier, i.e. before Lynn was in the picture, I probably would have said yes.

Eventually I told him something along the lines of "Hey, I don't really know how to tell you this, but I have a girlfriend. You're an awesome person, and I think there was a time where I would've said yes, but I'm not compromising my relationship" and while he took it well, he mentioned something about how this was the second time he's been rejected this year, which makes me think he's not on board. (He also was not aware I was bisexual, because I forgot that I didn't tell him. The pains of being very obvious about your sexuality, and forgetting that not everyone picks up on the stereotypical hints)

After the concert ended, I went home and told my mom about the situation. She said that I'm still young, and that she thinks I like John. She also told me that since I'm still young, I should be thinking about what I want, not what Lynn wants, and if I want to date John, I should.

We decided that I would go to school tomorrow and act as if nothing happened, and then we'd talk about it Friday night. She also reccomended I not tell John or Lynn about this until I figured it out, or my friends, so I figured I'd lean to y'all since on my main, you have been pretty helpful.

The thing is I don't want to hurt either of them, and I'm worried I've already made John a little hurt. Lynn has told me about people confessing to her and her turning them down bc we're dating, and when I brought up the question of her views on polyamory/open relationships, she said that she liked being loyal, although she didn't say anything about what she wanted from me.

Ideally, I'd not have this fucking problem, but since I do, I think that I'd want to date them both if possible. I feel like if I don't see what happens with John, I'm going to regret it and he'll be the "one that got away" or something, but I also feel like Lynn and I have a serious connection, and could be together for a long time.

Should I tell John I like him a little too? Should I tell him I'm breaking up with Lynn? Should I break up with Lynn? Should I tell Lynn about this and ask what she thinks? Should I ask Lynn if she would be okay with me having a boyfriend as well as a girlfriend (her)? I have absolutely no clue what to do, and I have already had one panic attack and would like to avoid having another one, especially at school tomorrow.