meeting the mom

My boyfriend lives across the country and I'm visiting him in a month. He asked me if I would meet his mom. I said of course but I'm super nervous. He's important to me and he's obviously important to his mother so I just don't know what to do or expect. He said she would love to meet me but I'm just nervous she won't like me, and just people act differently from the east and west coasts so I don't want to say or do something she'd find offensive or vice versa. I'm probably overthinking, any advice?