is he just doing it wrong or is something else wrong?

So I'm 19 and a virgin but I have been with this guy for a year and he fingered me for the first time yesterday. It felt good at first but eventually it really hurt and he couldn't really find the opening to my vagina. I have had trouble putting tampons in since I first started my period and have never successfully gotten one in. I'm wondering if maybe my vagina is shaped weird or if it's just really small of if I'm just a complete inexperienced idiot. My mom isn't really someone I can talk to about this because my sister kinda went crazy when she was in high school and began having sex with a lot of people. I don't judge her or anything but my mom is afraid I'm going to do the same thing so I can't ask her about this stuff. Does anyone know what is going wrong?