The question is what can Villain be calling you with on each street?
Flop
- a worse hand like KJ, QJ, JT, J9s, A8, A4
- the same hand AJ
- overpair was not very likely because no 3bet
- underpair like TT, 99, 77
- a set with 44 or 88
- air with hands like Ax, Kx
- a speculative hand like QT, T9
Turn
- a worse hand like KJ, QJ, JT, T9
- the same hand AJ
- a better hand like J9s, QT
- overpair was not very likely because no 3bet
- underpair like TT
- a set with 44, 88, 99
- air with hands like Ax, Kx of hearts
One may argue that a set or straight would raise the turn but given that you are still betting, there's a chance that they would let you bet the river yourself rather than make you fold. Slowplaying is definitely possible.
If you put all of those hands into pokerstove or similar, you are doing quite well against most of them. The ones you are not doing well against are those that took a weird line ie: not 3betting QQ+ pre and not raising the turn with set/straight.
Having said that, if you didn't have the A kicker I would most likely be looking to slow down a bit to avoid building a big pot with an "ok" hand. It kind of depends who you are playing against. Against a good player, it is unlikely to get the 3 streets of value and it is likely they are holding a better hand, so slowing down makes sense. Against a fish, you take them to value town.