Should I tell her how I feel now or later?

I've known this girl for about 6 years and we are good friends. Recently I've fallen for her but I'm not sure if she feels the same about me (I don't think she does, but again, I'm not sure). Her and her mom are really close and her mom goes in for surgery in a couple days. It's not like life threatening, but she won't be able to walk for like 3-6 weeks. I'm uming I should wait until her mom is all better before I tell her how I feel? I don't want to put too much on her proverbial plate right now...