I expressed colostrum early, because I had gd and one of the midwives recommend I do so that in case bub needed to be supplemented.

Can't remember exactly when I started, somewhere between 34 and 36 weeks. I didn't have any issues, started only getting small amounts, about .5ml and gradually increasing. My left side always produced more and still does with milk.

Dd was born at 39+2 all fine and dandy.

My milk came in as per normal after birth and I have HEAPS!

I think it was a good thing, even just from the point of view of being comfortable with your breasts and knowing how they work.

Hope it helps for you