Why is my newborns eyes getting lighter?

Stupid question I know lol.

My daughter was born with blue eyes, like every other baby!

Although four weeks later and her eyes are super blue now and turning lighter around her pupil.

Me and my partner have light brown eyes.. although both my parents have green and blue eyes. Mine are a little hazel.

Everyone says her eyes will stay blue but I’m adamant they will go brown.

Does most babies eyes get lighter before they change?

It’s not important I love her regardless of colour I’m just a little confused as to why they are going lighter..