NL25 AA facing rr on the flop

[Shephard]

maybe this is very standard, but what is the correct play here when you dont have any good reads? i really think this is very often a set, should i raise more preflop?

PokerStars No-Limit Hold'em, $0.25 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver Cards)

BB ($20.60)
UTG ($6.45)
UTG+1 ($25.10)
MP1 ($5.55)
MP2 ($25.25)
MP3 ($29.25)
CO ($24.65)
Button ($11.10)
Hero ($37.50)

Preflop: Hero is SB with , .
UTG calls $0.25, UTG+1 calls $0.25, 1 fold, MP2 calls $0.25, 3 folds, Hero raises to $1.5, 1 fold, UTG folds, UTG+1 folds, MP2 calls $1.25.

Flop: ($3.75) , , (2 players)
Hero bets $1.75, MP2 raises to $4, Hero ?