My hair was the opposite when I was around your age. It still is normal for your hair to do that though.
I'm a girl. I'm 12, soon to be 13, and my hair used to be very curly and wild. I'm starting to notice that it's becoming thinner and "straighter"? Is that normal for girls my age?
I'm the opposite my hair used to be straight and thin,but now is really thick and curly , however Ive got a friend who's hair sounds like yours so - yes it is normal especially at your age as you're still growing. Just be grateful for thin hair as thick hair is IMPOSSIBLE to manage aha.