I've never tried a recumbent bike -yet.

Cycling is actually a sport that runners take up..after they have damaged their knees. Cycling is kinder on the knees but gives you still a cardio workout. But you need to do it on a properly fitted bike for you and also proper use of gears (do you know how to use 12,12,21, 24 speed gears?) to allow you to cycle more relaxed but faster on flats vs. proper granny gearing to help you get up those hills.

Many aches, pains on a bike are due to improper bike fit. Also saddle height and the geometry/length of bike.

Alot bikes are too long for many women's torsos. So a person is too stretched out.

Your knee problems...maybe are bike fit, saddle height and pushing your legs way too hard on your pedals (not using gear properly?). If your thigh/leg muscles feel too tight while biking, then loosen your gearing, if loose, tighten up.

One should shop around in a bike store or 2 and spend some time trying out bikes and asking lots of questions. And walk out if the bike mechanic doesn't treat you well.

Spend a few months and don't get discouraged to find the right bike. It took me 2 years...before I bought my 3rd bike. It finally fitted me. Made such a difference..now I go 20% more mileage and can climb hills better.

Cycling is a sport that women take up from their mid-20's up. I do think it's related to being a solo sport that relies heavily on your mental strength, endurance...and desire to be freed..qualities that women gain over the decades. It is harder for a 17-yr. old girl to cycle 100 kms. vs. a 40 yr. old woman. Trust me. If you have been pregnant and felt all those other natural physical aches...then come on, girl,...you can bike FAR.
Of course, I've never given birth in my life. But you get what I mean.

I was involved in running a women's cycling group for a few years. We had workshops on bike sizing /geometry for women, cycling nutrition, long-distance trip touring by bike, using your bike gears properly, etc. Also had monthly bike rides for women, ranging 30-60 kms. per trip. Some times we ended up at the beach, art gallery or picking strawberries.