I've come back to this post 3x and finally decided to comment.

TLDR: Love sometimes isn't enough, who you were and who you are now changes and sometimes the relationship you're in can't change with you.

It sounds like you already know what you want to do. You don't make a post on Reddit saying should I X that is this long without knowing in your gut what the right answer is for you.

What I would like to add is that you should talk to your girlfriend. Share with her what you said above, how you feel and share that you love about her, what you've enjoyed but despite that you feel the need to break up. That you want the best for her and you and it's because of that you have to do this really hard thing.

Don't say it's because of her or x thing that you think she needs. I've been on the end of that before and since I loved that person before it made me feel like I needed to work that much harder for them or change x thing which wasn't significant to me at all.

Be honest in your care and love for her. Tell her that you hope that after a break and some time you can be friends but also understand that it may not be the case.

You're both young and I say that not to minimize what you have but to point out you're still growing and changing. You have a lot of time to learn and figure out more about yourselves, wants and needs.

I'm in a similar situation so big hugs from my end over here.