I Don't Feel Anything During Penetration

Dear Dr. Betty Hello,
I’m 16 years old by now and I have been dating my boyfriend for 8 months. We have had sex by all this time and I have always experienced the same when he penetrates me, anything. Before penetration we normally masturbate each other and he usually plays with my clitoris, this gives me pleasure but at the same time I get super stressed and I just can think about him stopping masturbating me.