My Dad put me in t-ball one year when I was maybe 6 or 7. I always liked being in the outfield so I could pick flowers...hahaha.
As to exercise, modern young women can easily become obsessed with fitness. Media, (especially fitness magazines) contribute to this. For teenage/college age girls, working out often goes beyond being fit and healthy and is pure vanity. Unfortunately, in western culture, this is what is valued. It is also exploited by feminists because women are allowed to obsess about every detail of their body, but then they decide men are pigs if they make any comment about female appearance, even though they are bombarded by images of it everywhere.
While I have personally given up being a fitness fanatic, I do still workout, but by myself at home and not for hours a day, which can mess with the body. I am satisfied that I am able to maintain my pre-pregnancy weight and feel trim. I don't care if I don't have the exact same muscle definition as I did at one time, because sometimes that can look borderline unfeminine. I don't think it is attractive to purposely try to look athletic if you have a naturally feminine shape.
I do think it is very important for mothers to stay healthy. As it was already mentioned, most women do not have the same amount of physical work to do as they did 100 years ago. This, along with unhealthy diet/processed foods contributes to obesity which can harm a woman's fertility and raise the risk of pregnancy complications such as preeclampsia and gestational diabetes. I had a very easy labor and delivery with my daughter, and I do think that being fit may have helped me. My doctor cut me off from vigorous exercise in the second trimester, but I took long walks, did a lot of stretching, and used a resistance band. I think this helped me bounce back quickly after giving birth. Sometimes now I will do light hand weights, but if you were to follow the advice of say, Shape magazine, you'd be overdoing it with strength training.
Additionally, I don't think there is anything wrong with women working out to keep their appearance nice, both to attract a spouse in the first place and then also just to keep looking nice for a husband during the marriage. In the same way that a wife should strive to keep her home beautiful and comfortable for her husband, she should keep herself looking nice too. For some women who don't have much physical housework to do, formal exercise might be a part of this. I don't think that necessarily crosses the line to vanity.