I “can’t” make love with my boyfriend

Hello everyone

I’m 17 and I’m a virgin. My boyfriend and I have been dating for four months and we both feel ready to have sex together. He’s also a virgin, but he has already had experiences with other girls, while I’d never seen a penis before.

Yesterday we were home alone and when he tried put his finger inside I felt uncomfortable, so I told him to stop even if I wanted to have an intercourse with him. It’s like a physical feeling.

At the same time I didn’t feel like touching him there, even if I really wanted to.

I’ve always had this problem: I don’t masturbate and I can’t even insert a tampon!

I feel uncomfortable with my own intimate parts, even if I really want to enjoy new experiences with my boyfriend. I love him so much and I’m pretty sure he’s the one I want to lose my virginity with

Can you help me figuring out what my problem is? Thank you all in advance, and excuse me for my mistakes as I’m not an English native speaker