correct fold turn?

Depends on stat/reads but I think most of the time here your fold is correct. You will see some set of 3s that do this for sure, that called flop to get it on any safe turn. If he has any kind of opening range here on the CO, it is more likely he has 33 (if you think he would open AA or KK in position). From my own personal experience though, I am behind in these spots the vast majority of the time. KK is indeed possible if you think someone maybe called flop with KK and the flushdraw and have seen that happen in the past. GL

I couldn't fold unless there is some hard evidence from hud/notes. He limps from CO, which reduces a lot of AA/KK hands from this range. On the flop he calls, which reduces AA a lot. If he has Aces, the pot is a bit small and there are three different draws on the flop. Most of the time he would raise it imo. If he has KK, he needs to have a flush draw with it, otherwise his flop call is strange.

So unless he doesn't raise anything preflop, the only hand he could have there that beats you is KKss, which sounds a lot like raise from CO. Looks like oveplayed AK/33 to me.

I agree. Limping range will have way less AA/KK. I sigh call and note.