When did you experience nipple changes?

Mimi • Baby boy born in April 2020 👶🏼 loss in 2021 👼🏼 rainbow baby coming in 2022 🌈

I’m wondering when people experienced changes in their nipples during pregnancy? I’ve always had bumps on my nipples but today I noticed that a few of those bumps are especially red/darkening and swollen. Could these be the first changes? I’m exactly 4 weeks along