When can you start lactating?

Shannon • I'm a mom to my beautiful 12 year old daughter Rylyn. And Jahna Nicoletta 9/29/16 my beautiful baby girl!!!!💖👶🙏💖
I'm 22 weeks prego today, and my boobs are massive, I thought I drooled on myself, but it was colostrum, streaked with white....is it that to early to leak yet? I have a 12 year old who I breastfed for 12 months, and will Breastfeed this lil baby girl as well.....