I have been to two retreats and knew about 50% of the people. The last one I took a friend who knew no one and she had such a good time, she didn't want to leave.
At our retreats we sew a lot, eat a lot but most of all LAUGHT ALOT. I haven't laughed like that since high school and that's been many years. It doesn't matter how advanced you are. True quilters are always willing to help beginners.
It's a great place to share ideas and tips.
I would highly recommend you go. Wish I could do one once a month just to get my laugh winkles working!