like kellyp5820 said, you're only 13. I got mine when i was 13. I remember i was out on a skating trip with my class. I't does not come heavy the first time. I would suggest wearing panty linners too.
Take care.
u r only 13 dont worry about it.when u get them ull be wishing u didnt.
You will get your period. if your worried about getting it in school just start wearing panty liners