Girls only? is this my period?

Sorry for atrocios spelling I'm using my mobile. Well I'm twelve anfd have been getting discharge for about 2 yeaRs now and my hve bn developing.. I have pubic hair etc.. Anyway, Today I found a spot of blood on my panties and I think it is my first period? I'm not sure though.. I was wonderibg if it is should I bring a couple of pads into school tomorrow? Thanks