I have no idea what my IQ is. I definitely know what my present limitations are, and I think about them a lot (I'm a little obsessed by the limits on my willpower that keep me from e.g. spending 8 consecutive hours studying abstract algebra, or learning Haskell). But I'm not alarmed by them. I am naturally "good at" some things (I'm coming to believe that "good at" is almost a synonym for "enjoys/gets a charge from") and other things are uphill climbs for me. I try to arrange my work so that my uphill climbs are always for a reason. I think this is a healthier attitude than trying to gauge some very-probably-fictitious intrinsic "IQ" attribute to find my place in the world.
If you can write in complete sentences and in a conversational tone, you're doing fine on charisma. Having organized and been involved in HN meetups in the past: you are almost certainly not anomalously inept in social situations. We are not the funnest cocktail party in the world.
I came across this post because I have a saved search for "IQ" (historically, "IQ" has been a reliably marker for seriously gross threads) and not because I clicked through on an "Ask HN" about "coming to grips with your own mediocrity". I'd gingerly suggest that the whole notion of "coming to grips with mediocrity" is a bit toxic and crazymaking.