SOS! Is this an infection or what?

I'm 16 and I've been itchy and dry down there on and off for a while with really weird white stuff that can sorta be rolled into a ball Also, I've noticed a dried crusty white discharge on my underwear. All of this especially likes show up the day after I do anything sexual with my boyfriend. We've been together over a year and we havent had sex yet so its not like its because we didnt use protection because there is no need lol. I'm very hygenic and I've tried to keep it at bay for as long as possible (wearing cotton underwear, taking off my bathing suit immediately after swimming, not using heavily scented soaps, etc.) , but theres only so much i could do. Anyway I'm a little worried so if yall could give me some advice on what it may be and how to help my symptoms? I will tell my mom to schedule a gyno appt. if need be, but i worry she's going to assume the worst and like try to tell me its some crazy ass std or something (shes a nurse, she cant help it).

And yes I understand std's can be transmitted through oral sex, but the dates and the symptoms just dont add up. (Besides he's a working and commutingcollege student and im a dancer musician and an honors kid. We dont have the time to cheat)

Anyway someone help me I'm tired of feeling so lousy