when did your baby's eye color change?

Erin • Mama to 3 beautiful girls
My almost 4 month old still has blue eyes..they've gotten a little lighter blue.
Our four year old also has beautiful blue eyes. 
However my husband and I both have brown eyes. 
What are the odds that two brown eyed people would have two blue eyed children?? 
How old was your little one when their eye color changed?