I never had anything before birth and my son came out STARVING. He nursed every half hr for the first month. Super exhausting but he knew best, and brought my milk in within three days. The more baby nurses the more milk you produce. It's supply and demand so since you don't have a nursing baby right now, your doing fine :)
As said above you produce colostrum first. It is to bust your babies immune system at birth. You won't produce much and you wont necissarily leak. I never did. This doesn't mean it's not there or that you're not producing enough. You'll get your milk after you give birth.
You don't produce milk until after giving birth. You should be producing colostrum (white or yellow liquid that leaks) first. That will supplement your milk (yes it's still food for the baby) until your breast start to make milk. You can receive your milk right after birth or 24 hours to a week to get your milk in.
Thats A Good Question Cause Im 35 Weeks And One Day And I Dont Have Any Milk Either Ima Ask My Doctor