What Causes Itching In Vagina When Urinating?

Hi, this is really embarrassing but, I'm 13 years old, I'm a virgin, and (if this matters) I have had my period for about a year. By anyways, my vaginas really itchy. This started about a week ago. When I go pee, it burns. Not all the time, but sometimes and mostly when I go pee in the morning right after i wake up. (WHAT I'M ABOUT TO SAY IS VERY BARASSING) but, I wanted to know if it looked any different so I opened the flaps of my vagina and there was this white stuff. It wasn't coming out of my vagina and it wasn't liquidy. But it was flaky it came off but there was alot of it. I don't wanna go to my mom about this, so please help me!:(