you could have a yeast infection but im not sure that affects your period. they are easy to get rid of. you should tell your mom about it and have her get you some over the counter medication for it. if you cant tell your mom you can go look at the store to see what they have and can ask the pharmacist if you have questions
what are you worried about if you are a virgin you dont have to worried about being pregnant but as for your swollen vulva more info is needed