Milk Production

When does your milk start to come in? I had my nipple pierced pre pregnancy and ended up having to take them out around 8 weeks or so because or pain and swelling and now (26 weeks) I have some white goop like stuff coming out. You can tell it is kinda liquid but the outer part is more of a dried “plug”. One of them is pretty tender to the touch. Not sure if it’s my milk coming in or if I need to talk to my doctor. I just had my appointment so I’m not due to go back for 3 weeks.