Hi there. Newbie here seeking advice. Which model ebike should I get?  I'm 75, female, and just had a knee replacement surgery, so I obviously won't be riding until spring. I'm 5'3", about 160 lbs and very non-athletic. I live in a very hilly area so I want a bike that can get me up these darn hills. I'd like to be able to go 50+ miles between charges. Also want 24" wheels do I can support myself while stopped and still seated. Am I asking for too much?