Is this my period of not?

Im 13. I hv:pubic hair, breast hv grown, discharge, growth spurt, etc. I hv had cramps recently (not very strong ones). I saw my underwear earlier today and saw a light brown spot where the discharge is usually(not much of it). Then I just went to the bathroom and saw on my underwear now there is white/clear discharge now. Is this my period or what?