50NL 6m Line checkup with overpair

PokerStars No-Limit Hold'em, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($36.45)
SB ($49.50)
Hero ($50)
UTG ($84.35)
MP ($60.45)
CO ($17.10)

Preflop: Hero is BB with Q, Q.
3 folds, Button calls $0.50, SB completes, Hero raises to $3, Button calls $2.50, SB folds.

Flop: ($6.50) 9, 7, 3 (2 players)
Hero bets $6, Button calls $6.

Turn: ($18.50) T (2 players)
Hero bets $12, Button calls $12.

River: ($42.50) K (2 players)
Hero checks, Button bets $12.5, Hero folds.

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Villian is 52/6/0.7 over 50 hands.

How do you like my line here?

I think I call the river because I see an opp that bad doing that with a 9.

looks ok to me, but agree with iowaskins, although its close

River's too good of a price to fold. Anything more, though, and I like folding.