As you said, reads are important in this situation. If I understand you correctly, there is a raiser, a caller, you three bet and then the cold caller shoves.

If you are pretty sure they have a small pocket pair, calling would be correct because you are about 50% to win the hand, and there is a lot of dead money in the pot. If villain shows up with worse aces here (which they will a lot in my experience) this call is even easier.