Cup size

I’m 13 and I just started my period. I wanted a menstrual cup but I think we ordered the wrong size. We got a regular but after more research I found out that’s for women who have gave birth and I’m still a virgin. I don’t know if I should try to go with it or tel my mom bc it was $30-40 and she wouldn’t want to order two in such a short time. (Brand is saalt)