My mother doesn't trust me?

okay so I have over-protective parents, I'm not allowed to date and stuff okay I dont care about that, recently I've been talking to this guy and we became very very close friends, we actually became best friends and ever since, she started giving me nasty looks and telling me that I'm immature and things like that and he's the closest friend I have and I never want to lose him just because mom doesn't like him she didn't even meet him and she's so judgemental, help any suggestions on what to do how to let her loosen up a bit, she doesn't like when I have best guy friends, so..please help.