Overreacting or right to be upset?

Me and my bf recently got back together after breaking up for a month. He asked me if I wanted to go to the beach with him and his church this Saturday . I was really looking forward to it. Then today he tells me he told his family about it, and that him and his family are going to go so he doesn’t want me to go anymore because he doesn’t think I should be around his family since we are supposed to be taking it slow. Yes we are taking it slow but I have already met his family numerous times so idk why I couldn’t go? Idk it just made me feel shitty . Am I overreacting or no