need your help!!!

im going to have sex for the first time with my bf but im soooooo afraid about not being good for him i never told him about this and today i asked him what he likes in the bed he said you dominating me and i said its not what i like to do but ill try if he wants after that he saw this at facebook he laughed and said thats you in bed just because i told him i dont like being the dominant one and i feel bad about this i never felt confident about sex but its more than ever now what should i do😔😔😔😔😔