It can be when you first start and your period could be abnormal for you entire period life its nothing to worry about I am 15 and have had it for 1 yr and it is still abnormal so yours could become normal or stay abnormal.
if she has a boyfriend try and break them up without getting them mad at you. if she doesn't tell her gross things about boysI'm in that situation right now and I'm planning on telling her parent's...
If your right handed you wear it on the left, left handed wear it on the right. if you wear it on your dominant hand then it is more likely to get damaged because you do more things with that hand