I wear below-knee skirts and dresses exclusively* and have for a number of years. The one thing I have to say about What People Say About Skirts is:
When someone tells you that you “can’t do X in a skirt”, they are wrong.
Specifically, they are leaving out some critical modifiers. It’s not true that you physically cannot do various things - ride horse, climb tree, run hard - in a loose skirt such as normal people have historically worn. What they may not be aware that they mean is: you cannot do those things in a socially acceptable fashion, which generally means without a chance of anyone seeing your underwear/lack of underwear. If you are in serious danger, or are alone, or simply choose not to care about this, I promise you can do those things just fine.
(Personally, in my life I find that I can also shovel snow in a skirt, because my scandinavian heritage makes me get warm VERY fast when I’m exercising. Obviously snow is not Super Cold Weather, but: you can do it. It will kind of suck if it goes over the tops of your shoes, though. Get good shoes.)
*It’s not a religion thing or anything, I just hate shopping for pants and wearing pants that don’t fit right or have bad texture so much that I quit forever. If it sucks, hit the bricks!