I have seen my scalp when I part my hair since I was as young as 8. My friends didn’t see their scalp.

If your hair is fine, the part looks more see-through than when your hair is coarse. It does not mean that something is wrong unless you believe you are losing hair. I always tell people that when I was young, the grown-ups would rub my short hair for luck when they saw me. They did this because my hair was coarse and there was no see-through to the scalp.  If I asked you, I’l bet nobody ever did that for you and you agreed, that means that your hair is fine and fine hair never looks very full and the scalp is often seen through the hair.