Was I too quick to fold here? It was a min bet, but I figured losing more than needed on a hand where I had nothing wasn't a good idea. It's a clear fold if faced with a real bet. I'm not sure given that it wasn't, however. What do you think?

Party Poker No-Limit Hold'em, $ Hero (9 handed) converter

MP2 ($23.45)
MP3 ($47.6)
CO ($50)
Button ($116.75)
SB ($43)
Hero ($32.5)
UTG ($37.15)
UTG+1 ($40.75)
MP1 ($128.05)

Preflop: Hero is BB with 5, A. CO posts a blind of $0.5. SB posts a blind of $0.25.
1 fold, UTG+1 calls $0.50, 2 folds, MP3 calls $0.50, CO (poster) checks, Button calls $0.50, SB (poster) completes, Hero checks.

Flop: ($3) 3, 7, J (6 players)
SB checks, Hero checks, UTG+1 checks, MP3 checks, CO bets $0.5, Button calls $0.50, SB calls $0.50, Hero folds, UTG+1 folds, MP3 folds.

Turn: ($4.50) A (3 players)
SB checks, CO checks, Button folds.

River: ($4.50) K (2 players)
SB checks, CO checks.

Final Pot: $4.50