Is it true that once you took the helmet home, you can't change it to a different helmet, even to a smaller size? As a learner, I had no idea on how to buy a helmet. So I went out and bought a helmet (size large). Once I got home and looked at the manual and website, I found out that the helmet was quiet big for my head. Do you think I can change it to a smaller size, can the law help me here? I went to the store where I bought the helmet and the guy said he could not help me - I bought it last weekend. Please don't fire at me here.