I have had similar moments, worrying both about the social and the emotional maturity of DS versus other children we met. Actually I shouldn't call them moments, most of the Christmas vacation had me mulling over DS socio-emotional development.
We had to leave a Christmas party early because after playing grocery store very nicely with some sligthly older girls,, he descending into being totally obnoxious, annoying (switching off the lights) and hurting them (pinching) on purpose, then having a meltdown because they sent him away (apparently) saying they did not want to play with him ever again, then knocking over a little one on purpose, another try at playing with the bigger ones, another meltdown "they said I am not allowed to go back home ever!"
The other grownups would just roll their eyes at me "oh they have their ups and downs!" when I kept hovering trying to interfere, one father telling him "come on, don't believe everything girsl tell you!" To me, they just didnt seem to get it - after a certain point, there is no way for him but down and there is no way for him to nat take things seriously. There is no other way but hovering and being on top All.The.Time, pulling him aways physically from the lightswitch etc... so we just left to put him to bed.
We tried again for a New Year's Eve party at another family's place and we never left DS out of eye- or earshot for longer than a few minutes, kept shopping in their store so I could steer their play to keep them all engaged, constantly running interference, rushing over like lightning when one of the girls yelled "ow - stop it!", kept threatening at the slightest infraction (jumping too close to a little one for instance) "stop AT ONCE or granny will come get you" (my parents having agreed to pick him up after the kids' dinner to put him to bed so we could stay with DD) and we actually had a very nice evening! Sounds counterintuitive, I know, but we had it under control at all times. And I did not care whether people thought I was being weird heli mom - in fact, I had a chance to talk a little to our hostess, who we see rarely, about our four-year-olds and she said "you know, DD does this obnoxioxious thing in preschool where she runs at kids to hug them and won't stop, knocking them over - some of the other kids just oaugh and others lose it and it's embarassing..."another sensory seeker! I was so relieved- the two actually got on like a house on fire...Still, th other little girl , though only two months older, seemd MUCh more mature.
Everything is so much more intense. It struck me that even when DS is goofy, it seems more intense than other kids. When he is being serious, the same. When he is being sensitive - he shocked a friend who wantde to give him the story about Miracula fro Christmas, which he knw from the library, and he had a meltdown immediately about the story being "too sad - she can't find her shell and gets WET!" He seems much younger during those times, too.