Don't feel like going..help😭

Hi everyone I am 3 years with my boyfriend. And I got to know his mom and it's been a few times that he picked me up and brought me to his house to hang out with his mom. Well tbh I feel so uncomfortable going to his house. I have no idea why. It's like an hour drive from where I live. And he doesn't sit near me or in my area when I'm there. He just leave me to his mom and watches TV. And I am this kind of person, I don't like to go to other people's home for long. Like I am this shy type of person. I wouldn't know what to say or what to do, where to place my hands, how to sit properly. Where as when I am home(I live with my parents tho, still in school ,age 22 ) I sit however I want,grab snacks laugh while not being afraid thinking " am I laughing too hard?" So anyways long story short. His mother sister wanted to see me and her daughter. And my bf her mom will be there too. And you've guessed right they called me over for tomorrow, it wasn't planned tho ,they told my bf like an hour ago.

I don't feel like going ,I told him that I am not sure ..he asked why ,I said I have no idea.. Like I don't know what to do. What will I do there? (I am the only child BTW I have no social skills😭) if I go I know that I would be looking at the time until it's time to go home.. Btw my boyfriend is 30 years old.

What to do 😭..please help me out here I would really really appreciate it