Glenda,
We are all different and there can be no hard and fast answer. I guess, from your question, that you have not been on PM that long and have not yet felt any ternderness. When I first started, the first thing, I noted was that my chest felt fattier [I used to joke with myslf, that my chest had been upholstered]. Then my nipples began to increase in size and becomepermanently erect; next they began pointing, slightly towards the side, rather than straight ahead. All of this was before any feelings of tenderness began.
Tenderness came later. The day I noticed it, I was walking the dogs on the shore of Crafnant Lake and I recall I only had a shirt on, so it must have been May or early June and I had started in PM in mid Februry. In late March I bought a Morris Minor van and I recall that I went to see it, I was aware of a jiggle under my shirt, when I drove over a bump.
I hope that is of help.