Colustrum, lactating?

peachy

Hello, is making colustrum and lactating the same thing? Also how long does it take the colustrum to turn into real milk? I'm 21 weeks now and I've bin having dried colustrum on my breast from about fifteen weeks or so when I wake up in the mornings. But recently when I'm holding my nipples to clean off the crust some colustrum comes out. Is the colustrum going to turn into milk soon, also does it run out. Thank you