Body weight exercises are best before you start a weight training regimen.
It allows your body to strengthen your ligaments and tendons better and at the same time it helps the body to gain strength as well.
I have two styles of push-ups. Doing push up with your knees bent are best suited for women or men with less upper body strength. This does not mean that after gaining the strength women should keep doing this style. The women can also progress to doing full pushups.