Thank you #AnnieBrooke. I will try to stay away from her for now.
I think that if you loved her enough to want to marry her, you would know it. The kiss sounds like an impulsive act, and also sounds like you tried admirably to avoid letting the physical take over so you would not wind up in bed. It really doesn't sound like you have a lot to feel guilty about. You got out of there and stayed away, an honorable move when you weren't sure of your motivations. In your position, I would stay away from your uncle's house until you hear she is married. She might have a crush on you, but you do not have one on her, you just get along and you had one impulsive moment. She will take any civility on your part or friendliness as a signal that it is possible for you two to get together in a love relationship, and I don't sense that you want that. For your own safety, stay away. She will get over it.