God mother question

Jordyn • Married to the love of my life. Mom to Vivian Claire born 2/5/17. Baby boy due 6/29/19
I am a Protestant Christian and am having my baby in February. I really wanted my best friend to be the Godmother of my baby girl but my mother in law insists that only Catholics believe in having godparents... Can anyone clarify this issue for me? I'm kind of confused! Thanks!