5 handed. BB is pretty donkish, CO is an unknown.

Hero has Ac 7h in SB

CO calls, button folds, hero completes, BB raises, Co calls, Hero calls

Flop Ah Ks Qd

Hero checks, BB bets, Co raises, Hero folds.

Any read on BB other than donkish? If BB is tight with his raises I would fold, if he's loose with them I'd want to call the 2 bets and see if he 3-bets/what happens on the turn.

CO limping instead of raising tends to make me think he doesn't have 2-pair or a good kicker with his ace. I think you're splitting this pot a lot, I'm not sure if it's worth staying in for the half of the pot though.

There are my random thoughs that hopefully someone can expand on and come to a better conclusion :-)

Raise pf.

Flop fold is fine in such a tiny pot.