Opp's stats were 51/15/1.0 over 95 hands. How is this line with top and bottom pair? Check behind or value bet the river? If you value bet, was my bet too large?

PokerStars No-Limit Hold'em, $0.50 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP3 ($61.30)
CO ($19.10)
Hero ($60.25)
SB ($61.30)
BB ($29.40)
UTG ($29.95)
UTG+1 ($133.45)
MP1 ($11.25)
MP2 ($51.95)

Preflop: Hero is Button with A, 2.
1 fold, UTG+1 raises to $1, 4 folds, Hero calls $1, 2 folds.

Flop: ($2.75) 2, A, 6 (2 players)
UTG+1 checks, Hero bets $2, UTG+1 calls $2.

Turn: ($6.75) 3 (2 players)
UTG+1 checks, Hero bets $5, UTG+1 calls $5.

River: ($16.75) 8 (2 players)
UTG+1 checks, Hero bets $15