What should I do?

My mom does not like my friend (who is actually my boyfriend but I don’t think she knows that). She met him and was asking a bunch of questions about him. She was okay with him until she found out he is 25. I told him not to say anything but he wants to be honest with her. I appreciate his honesty but my mom is against older guys because of my past relationship. A lot of bad things happened in my last relationship but I feel that age has nothing to do with the way he behaved. For example, if a person is manipulative then they are going to be that way no matter how old they are. I’m 18 and I have always had an interest in guys that were older. I may not be the most mature person on this planet but I have no interest in guys my age. My mom’s argument is that I have nothing in common with a guy in his mind twenties but I feel like its not right to judge every guy based on one guy’s mistake. By the way, my mother is the type of parent does not let me go out :/ so that alone makes it harder to talk or be with anybody. What do you guys think? I want to be with him but I don’t think it is fair that he has to go through what I go through (not being able to see each other).