Need some advice?

victoria
My boyfriend and I have been together for a while, he always comes over to my house, we never do anything that's makes us look suspicious to my mom, we stay down stairs in the living room. In pretty sure she likes him. But the problem is I ask her to go to his house and it's on the beach so it's not like we don't have anything to do but every time I ask she sais no?  I just don't understand why and I'll ask her why I can't go over and her reply is becaus i said so? Idk seems silly but it gets on my nerves.