When Do You Guys Experience The Development Of Breastmilk During Pregnancy

Recently I went for prenatal massage and was told that my milk glands are emptied. According to the masseuse, by 29 weeks of pregnancy, I should have milk produced by now to prepare for new born. The masseuse also told me that all my milk glands seems to be blocked and needed further treatment. Thus, I'm really concern. Can anyone share with me when do u experience milk production? Is it all will be after 28 weeks of pregnancy or after u have delieved ur little one?