$25 NL, KK , Ace falls on turn, played too passive?

[FearNoArt]

PokerStars No-Limit Hold'em, $0.25 BB (9 handed) Hand History Converter Tool (http://poker-tools.flopturnriver.com/Hand-Converter.php) from FlopTurnRiver.com (http://www.flopturnriver.com) (Format: 2+2 Forums)

MP1 ($10.35)
MP2 ($22.20)
Hero ($38.10)
CO ($8.70)
Button ($26.05)
SB ($35.55)
BB ($32.65)
UTG ($33.05)
UTG+1 ($14.90)

Preflop: Hero is MP3 with K/images/graemlins/diamond.gif, K/images/graemlins/heart.gif.
<font color="#CC3333">UTG raises to $3</font>, <font color="#666666">3 folds</font>, <font color="#CC3333">Hero raises to $5.75</font>, <font color="#666666">4 folds</font>, UTG calls $2.75.

Flop: ($11.85) 4/images/graemlins/heart.gif, Q/images/graemlins/spade.gif, 3/images/graemlins/club.gif <font color="#0000FF">(2 players)</font>
UTG checks, <font color="#CC3333">Hero bets $6.5</font>, UTG calls $6.50.

Turn: ($24.85) A/images/graemlins/heart.gif <font color="#0000FF">(2 players)</font>
UTG checks, Hero checks.

River: ($24.85) 4/images/graemlins/club.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">UTG bets $20.8 (All-In)</font>, Hero folds.

Final Pot: $45.65

No reads on Villain, just 13 hands into session. What are your thoughts ? Re-analyzing this hand, my flop bet looks too weak, i'm thinking 3/4 to pot size is what I should have done. When the ace falls on the turn, should I fire another shell or check as I did ? Tear this hand apart.

[abarrenfuture]

Raise more pf, id make it 8-9. Bet near full pot on the flop.

By checking behind on the A, youre pretty much telling villain to take the pot away from you IMO. As played, I think folding the river is probably best, although I could see someone with a Q doing this

[orange]

This looks fine. I doubt he does this with JJ.

[FearNoArt]

When the turn card hit it kinda froze me, since he just smooth called my flop bet. He may have thought I was just C-betting and called with Ace high or some medium pair, partly why I froze when the Ace fell, I was thinking he possibly had QQ,AQ,A-rag. If I bet the turn, I pretty much have to put my whole stack in with the pot being $25 and $25 left in my stack, i'm either WB/WA. Maybe betting as small as I did on the flop left me without a true sense of where I stood ..

Would a post oak bluff after the ace falls be a good counter to his call on the flop ? Post oak will certainly look like i'm trying to induce a re-raise, (to me it would look like such a puzzling bet into a pot that large) or does the post oak there just look weak?