My naturally straight hair turned curly, help?

I was born with naturally straight hair until now, my hair turned curly. So now my hair just dries curly and I don't know how this happened. I used to have really long hair so the curls were more like waves and it was only a few pieces of hair so it wasn't noticeable but I got a haircut today and the hairdresser cut it way too short so now it's shoulder length and it turned even more curly and noticeable. I have no idea how this happened, I'm only 14 years old but I'm turning 15 in two months. Help?