I have a question for you:
Why are you maintaining a relationship (even if it is limited) with somebody you evidently have nothing in common with, and that o top of that, makes you uncomfortable?
Are you just being polite? Tell her bye bye. Your age is different, your stage in life is different, your interest and life style are different.. Tell her she is a good person, but you WANT to move on to other friendships.

gab