hehe, thats what sexually active means. well i heard been really skinny can effect ur period, but u should have or pretty soon get ur rag. this is a medical problem if u dont get it by 18. u should go get check by ur doctor. but i believe its ur weight causing ur period to be late. i wouldnt worry too much about it, (its not all that cracked-up to be

). plus worrying will only be makin it worse. wish u the best.