Great game - thank you!
Also, if I don't choose to go the girlfriend route with someone, can I change my mind later? I'm worried about locking myself out of other content by going down that route now but don't want to lose the option later.
At the moment you can't change your mind (except with the patreon cheats), but also you won't lock yourself out of anything right now. You can have multiple girlfriends. It may affect the ending, but I haven't fully decided on how much yet, plus the end is still a ways out.
I'd suggest becoming girlfriends with whoever you like :3