Where am I? (A little rusty)

[directscooter]

Sorry for no HH, I am at work. Just back off a three week break and can't decide if I played this too passively or not. Villain is 50/0 in only 14 hands, so not sure if I can really count that as a read.

Villain $100
Hero $150

Hero has A [img]/images/graemlins/heart.gif[/img] A [img]/images/graemlins/club.gif[/img] UTG

NL $100 Hero raises to $4 and get 4 callers including the Villain in SB and BB.

~ $20 in pot, flop K [img]/images/graemlins/diamond.gif[/img] 8 [img]/images/graemlins/diamond.gif[/img] 3 [img]/images/graemlins/club.gif[/img]
Villain leads $3, BB calls, I raise to $20, all fold to Villain who calls BB folds.

~ $63 in pot turn A [img]/images/graemlins/diamond.gif[/img]
Villain checks, Hero checks

~ $63 in pot river a blank
Villain checks, Hero bets $25

The $3 flop bet screamed I am an idiot looking for a cheap card to complete my flush. Then when the flush hits and I hit my set, he checks (normal donk slowplaying a made flush?), so I take the free card hoping to fill up on the river or see how he plays it.
River, since he checks, I am assuming he does not have the flush and I really have no idea what kind of hand to put him on, so I value bet a little less than half the pot. If he comes back over the top all in I have a tough decision, but how often does someone check the turn and river like that.

Thoughts?