Why are young girls taught to be ashamed of their body hair?
I started shaving when I was eleven years old. Kids and teenagers can be so mean. Looking back on it now, I want to shake my younger self by the shoulders and tell her that body hair is natural. Everyone has it, and anyone who has a problem with girls/women having body hair can have a fit.

My pits are dark and hairy now. Every so often someone will do a double take. I feel eternally grateful to no longer care what people, especially men, think of my appearance. (Being a dyke is a blessing, but that’s another post.) I haven’t shaved in ages. But back when I used to, who was I trying to please?
There just comes a certain point in a young girl’s life when she is embarrassed and afraid of her body, and her mother, once in those same shoes, teaches her how to hold a razor and shave without drawing blood.

Sometimes children look at me and I know they have never seen a woman who doesn’t have bare armpits and legs. I see questions in their eyes, forming on their tongues. I wish they would ask. So I can tell them you can do whatever you want with your body until the end of time. Who gives a damn what anyone else thinks.
I do not blame my mother, who held the blade for me when I was eleven and shaving for the first time. But this is armor. My hair isn’t for the people who don’t get it. When I lift my arms in a sleeveless shirt it’s for me.
I'm not really of a generation or family where shaving is a must (who knows, maybe if I stuck my hairy legs out maybe someone would confirm that it is a must). However, I completely agree with your point and I like that you're sticking out for women against immense beauty standards! We do have a choice and should feel natural in our own bodies and not have to deal with criticism for something we can't help.
'When I lift my arms in a sleeveless shirt it’s for me'. I loved this. This is exactly how I feel. I've actually been told to wax since I was eleven, and when I started shaving (bc waxing requires pain, time, and money) my mum thought it was disgusting. Fast forward and I don't really shave that often either.