I first took my daughter to a group when she was about to turn one, as everything I fancied doing had previously coincided with naps or feeding. It was a group called Chatterbox, a little like Sing & Sign, and was run by a qualified speech therapist - you turned up and paid on an ad hoc basis.
That first session was daunting on paper - we sang songs together to help with the signs we were learning, had a coffee break and got some toys out for the kids, then cleared up for a final few songs. What made a massive difference was having a really relaxed, friendly leader, who ran the singing activities as a circle on the floor - no huddles or groups, just everyone together. We all had an activity to focus on, and lots of laughs when a child escaped into the middle of the circle, plus it was great to see our kids enjoying and participating in the songs and actions. By the time we had coffee, everyone was relaxed, and got chatting naturally as the kids played together; I got talking to a few mums who knew each other from another group, because our kids were playing in the same area, and the next week they all greeted me and asked how my week had been. The second session was the week of my daughter’s birthday, and everyone sang happy birthday. Within a few weeks, I was going for coffee afterwards with the mums I’d met, and they became my first ‘mum’ friends. We’re still in touch on Facebook, although our kids all ended up going to different schools.
i won’t say there weren’t less friendly parents there, or that there weren’t children there who were pushers, biters, smackers etc, but on the whole the mood was relaxed and it was easy to steer my daughter away from annoying situations. The group leader gave us some great activities to do, that brought real benefits, and her friendly attitude dictated the tone of the group.
Please don’t dismiss all groups on the basis of one awkward hour. The number of people saying they tried once and never bothered with any other groups is amazing - why would you give up on something you want to do, or that benefit your child, so easily? (That’s a general ‘you’, not specifically the OP). There are literally thousands of groups out there, with millions of individual parents - not one big clique determined to cold-shoulder you. As others have said, some people may be so new they don’t realise you’re also a newbie - they may be waiting for you to welcome them! Some people will be barely functioning and not have the mental space to make smalltalk or realise you need help. Some might be just as shy as you, but if you’re not approaching people it’s not fair to expect them to, either.
I hope everyone who wants to go to a group gets what they want from it - whether that’s lasting friendships or simply a space to be out of the house with more space for their child to play with new toys.