To attend family events?

I've been with my boyfriend for about 11 months now and he's my third, while I'm his first.

I met his whole family (grandparents, aunts, uncles, cousins etc.) for the first time a month ago during his grandparents anniversary. His family all seem very nice, but I got really stressed when I was there because I'm a bit shy and not much of a conversationalist, so I felt a tad awkward. I guess I felt like it was a day of judgement because they were meeting me for the first time too. Didn't really know how to approach his family and make conversation. Thankfully I made it out alive!

My boyfriend invited me to go for his grandads birthday dinner next week but im still contemplating if I should go or not. I just don't like getting stressed at all these social events because I feel like i just stand around and not know what to do.

I really love him though. He's made me happier than my past relationships have and he really wants me to join him. Should I just suck it up and attend the party? I have to do it sometime sometime anyway... I've been invited by his family for Christmas too.

Help! Opinions!

P.s some advice on what to talk about with the family too would be vety helpful!