My boyfriends mom invited me over to meet her family??

I'm away at college but my boyfriends mom (he's still a HS senior, I'm a college freshman), whom I haven't seen in months, texted me inviting me over on Saturday to meet my boyfriend's cousins and their kids. I said that I'd love that, but I'm nervous! I've met my boyfriends immediate family of course (his mom, dad, and brother) but haven't met any extended family so I'm nervous!! I want to make a good impression but I always seem to shell up and get awkward in these kinds of situations. My boyfriend and I are nearing our 3-year so it has to happen eventually, but still nervous 😓 Any advice??