When did you start to lactate?

Kellie • First time mommy to a babygirl named Lillie ☺️💕

So right now I’m 23 weeks pregnant and I’m not lactating. I first started having some colostrum at about 17-18 weeks including about 5 droplets of actual milk from each breast, but it has stopped since then and I’ve had no sign of lactating since... is this normal?