When should I expect my milk to fully come in?

Angela
Our son came into the world on 12/29/16 and I'm not sure if my milk has come in yet. It seems like he is feeding properly however I haven't felt that engorgement feeling yet. Every Mom I have talked to has said that I will KNOW When my milk comes in because it is painful however I have not experienced this yet. My son was feeding a lot more frequently the last few days however today he seemed to be on about a 2 or 3 hour schedule. Any thoughts would be greatly appreciated