sex & period

i’m 15 and i haven’t started my period yet. i haven’t had it once in my life but i had sex a few months back. i bled during sex and only a few days after sex. i haven’t had sex anymore after that but i haven’t been on my period since when we did have sex. i’ve had discharge for over 2 years but recently i’ve been noticing some spotting. i’ve been wearing a tampon recently and it’s very light. but i don’t know why it’s so delayed and i’m not sure if i started my period or if this is just normal. i haven’t been noticing blood or spotting for 3 months and all of a sudden i have. so i’m not really sure what it is