As soon as you want tbh as long as there’s enough hair I don’t see the problem doing small styles
I started @ 4 months. Just little ponytails. She was born w/ a lot of hair.
I started doing it properly at 1.5 years old just so she got used to me doing it
I’d start after 2. My daughter has a lot of hair, and I braided a cute valentines heart on one side in February. She now has a bald spot in the front of her hair. It’s growing back, but I definitely regret putting too much tension on her little head.