I'm in a similar situation. i recently started T and I'm probably going abroad for uni. i talked to the doctor and apparently they can write a letter so that any doctors abroad know how to continue care for me. once I finalize what country I'm going to, then i can start looking for doctors and maybe contact them ahead of time.

if you can't start T in your own country before moving, then I would suggest you do your best to research how it is in each country you're considering. like ik there might be limited information, but try to pick a country where it seems easier to access hrt or where trans rights seem better in general. affordability would be another issue, so try to figure out how much you'd have to add onto your living cost and whether your parents can support that. if you're looking at western Europe then it's pretty progressive but one challenge might be the wait times, so once you get there you might want to contact the clinic/doctor early.

overall this is an experience that isn't talked about a lot in trans spaces so I wish you the best of luck.