Long-distance crush/hook-up
(sorry in advance for how cringey some of this might sound)
First of all I should probably mention that I have 0 experience with relationships and such, but since last March I've been in an nsfw-centred discord server for a while, and gotten to know a couple of people. One of them I've been talking with a lot since, and while it started out as mostly a sexting thing (we've even exchanged nudes a few times) I feel like we've gotten close as friends too. Even though we live in different countries (they're in the US, I'm in the UK) they've said a few times that if we're ever in the same country they'd be happy to hook up; in fact they're looking at coming over to do study abroad next winter.
The thing is, that's obviously dependent on the covid situation at the time, and given the distance between us it's unlikely I'd get another opportunity to see them if that falls through. They've also started looking on apps like Tinder and such for people 'closer to home' to hook up with, and while I obviously understand why and I wouldn't dream of trying to stop them, I just can't help feeling jealous. Like, of course I wouldn't expect them to wait or anything, but I feel worried that if they do come over in ~9 months' time then they won't be interested any more.
Another thing is that I think I've actually started crushing on them, and while that obviously makes the above problem worse I also feel like they might be getting tired of talking to me. I'm known to overthink a lot of things, but it just seems like they're never the one to start a conversation, and that it's usually me that tries to keep said conversations going. It's gotten to the point where I'm physically feeling pangs of jealousy when I see their messages in the server because I feel jealous that they don't talk to me with the same enthusiasm.
I know I probably sound very selfish with this, but I just really don't want to be feeling physically ill from stressing over all this for the next nine months, so I'd really appreciate any kind of advice.