Is it normal it normal I often roll up one sleeve but not the other.

Nope, wearing long sleeves and rolling them up helps a person regulate their temperature better. When you're going from one temperature to the next, this is really useful. If you're cold, drop the sleeves, if you're warm, roll them up. If I'm at home wearing slacks, I do the same thing with the pants legs.

But I always roll both sleeves or pants legs up, never just one, that's kind of weird... But maybe it will catch on, become a fashion statement. You never know.