I can't comment on the parenting groups because I eschewed the traditional mommy stroller circuit in favour of maintaining my adult friendships from before DS was born. I'm not a latte-sipping, zumba-and-compare mother in jazzercize tights. If the groups aren't a fit, don't attend.
From my experience, in those early years, most other parents mean no harm by their questions. Parenthood is a bewildering learning experience for everyone, and the miracle of seeing your child grow up (at whatever ability level or temperament) is a wonderful, confusing marvel to behold. Every child and every milestone is a cause to be celebrated. The insecure parental competitiveness does ratchet up in the face of your child's expressed abilities, but it's nothing that can't be managed or dismissed. Find support here; the community and collective wisdom are unparalleled. Maintain adult relationships with people you genuinely enjoy and seek out interest based activities for your DS as he grows to find your local tribe.
My advice: give your child what he needs when he needs it, as only YOU are seeing him so intensively to be able to appropriately judge his needs. You (and your DH) have the unique benefit of knowing your DS before he knows himself because...apple, tree.
Parenting high needs children is exhausting, thankless, and often requires inordinate levels of patience. I worked in a career with 90+ hour weeks, extensive travel, and difficult personalities, and that had nothing on my 3yo in terms of intensity of demands. You will adapt. It sounds callous and pithy, but you will. You have no choice but to evolve or burn out.
On the flip side, you are in for the best treat, too, and it FAR outweighs the costs. Your child will be interesting beyond belief, exciting, keep you young and engaged, draw you out of yourself, make you test your beliefs, and be a source of tremendous pleasure. It's easy to get caught up in the mindset of otherness and trip yourself up in a negative loop of counterfactual scenarios. But ask yourself-- would life REALLY be better if your child was more like everyone else? Are most of the people you enjoy being around outliers? Are you?
At 3.5, my son can make me laugh so hard at his jokes that I can't breathe, and he's more interesting to discuss philosophy with than most adults because he sees possibilities most don't. Brutally honest confession: I don't enjoy being around most children, but I'd travel halfway around the world for an hour with my son. He is a phenomenal guy, and I am so grateful to be there with him as he grows up, even if it means I play second fiddle.
The next year will be a hard one, but also a rewarding one. Your son will start to more obviously develop his own identity and ideas, his thought process and humour will mature, and you'll be his guide in the process. Framing is key: if you can view his behaviours as genuine needs and label them positively, you will have a much easier time supporting his seemingly endless quest for learning in good cheer (even at 3am, when he has woken you for the third time, and is asking you some esoteric philosophical question when all you want is some sleep.) And, as much as possible, ensure that what you do with him is fulfilling for you.
But again, lean on this community heavily. That's what we're here for.
