My partner and I both used to attend an in-person autism group, that's actually how we met.
But there were a handful of difficulties with it:
1. I hate to word it like this, but we were definitely "higher functioning" than everyone else there... most people couldn't hold a proper conversation, most were living at home with their parents and needed a lot of support, and most only talked about the same repetitive topics over and over and all of the conversations were one-way. Most people weren't particularly worldly or aware of things either. Very different from the conversations I have both with people on this forum, and other autistic friends in real life, so I know that conversations with autistic people can in fact be reciprocal. This was just a skewed subset of people with higher support needs.
I'm not trying to say anything mean, and I'm sorry if this has come across that way. The majority of them were very nice well-meaning people, we just couldn't relate and the interactions were quite awkward.
2. Even with the first point stated, we felt a bit like we were being judged for having more "mainstream" special interests (dogs, sports, farming, construction, travel, home improvement/DIY, art, outdoors, etc.) Everyone else had very oddly specific, niche, off the beaten path types of interests (think along the lines of collecting vintage toaster ovens, obscure movie trivia, 1950s airplanes, furries, etc.)
I'm not in any way saying there's anything wrong with having unusual interests, and very niche specific interests can obviously be cool and fascinating. We just didn't like that the general attitude towards us kind of felt like we "weren't autistic enough." Both of us being very extroverted by nature also put us at odds with some of the personalities in the group.
3. The nail in the coffin for both of us was when I was befriended by a guy who ended up stalking me.
Without going into too much detail, this guy would spam me with upwards of 100 text messages a day, even when I wasn't responding. My partner and I would go somewhere for the day, and then very shortly afterwards the guy would send me a photo indicating that he was at said location. I ended up ceasing communication with him altogether and he continued to spam me with hundreds of messages a day, until I blocked him shortly after. When I blocked him, he used phone number generating apps to continue to contact me. I was absolutely terrified. It got to the point where we brought both of our cars into the shop to make sure they didn't have trackers on them. My parents actually ended up getting involved and even giving a detailed account of this story to the police (not that anything was ever really done about it, but that's another story.)
Thankfully, after we moved a ways out of our previous town, we never saw nor heard from him again. I've gotten mixed responses on whether or not a restraining order or an order of protection would've been necessary, but it's a moot point now as we've never run into him again. Hopefully it stays that way.
The stalking experience was what really ruined it, although we were beginning to feel a bit unwelcome and uncomfortable anyways. Not sure I'll be going to any more "real life" autism groups because I'd worry that it would be more of the same.
Sorry for such an uncharacteristically negative and bitter-toned post, but my experience was overall just not good and I hesitate to sign up for another such group.