You should take it off your chest before you leave, she will most definitely highly appreciate your honesty and you being vulnerable and open about your feelings. It’s admirable that you’re acknowledging the depth of your emotions for her, and I believe you should let her know about it.

Long-distance relationships are certainly a thing, and if that makes you uncomfortable, you can opt to not engage in one. However, she deserves to know that her feelings are unrequited (That, if they’re genuinely mutual, and you’re correct about your assumption regarding her also catching feelings for you).

Be sincere and also tell her about your inner struggle when it comes to your departure and the fact that you’ll inevitably part ways. You may come to a common agreement together and you’ll feel much more relieved after confessing. Not to mention, you might be able to make it work, but it all depends on the nature of your bond.

And in case you’re wrong about her liking you back, you have nothing to lose, since you’re leaving anyways. There’s nothing to lose, only to win, so I would suggest you think this through and make your decision based on the balance between the pros and cons. I wish you the best of luck!