villain had just sat down

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

Button ($49.25)
SB ($29.50)
BB ($46.45)
Hero ($143.45)
MP ($56.80)
CO ($77.40)

Preflop: Hero is UTG with A, Q.
Hero raises to $2, MP calls $2, 3 folds, BB calls $1.50.

Flop: ($6.25) 6, 5, A (3 players)
BB checks, Hero bets $5, MP folds, BB raises to $13.5, Hero ...

Calling is right out, I really want to push over this. But I puss out and fold. Is this weak? I know I'm going to have to toughen up my game, but I'm doing very well by people just donating stacks so I'm having a tough time with these smaller edges. Especially since everyone is generally so passive I kinda freak when faced with aggression (because usually they do have a hand). FWIW, if villain is $30 this is insta-push for me.