Is it normal that i rub the seams of my shirt between my fingers?

Since I was born I would rub the seams of my t-shirts between my pointing finger and my thumb and i'm very picky on what kind of seam it is. My mom said that I did it on her shirt whenever she was breast-feeding me. I'm in high-school now and find it kind of embarrassing that I can't break this weird habit but I almost don't want to because it feels good. I'd feel a little better if I knew someone else did the same thing.