Being a godparent?

I kind of straddle the line between atheist and agnostic. Solidly not Christian. I go to church maybe once every few years when I’m visiting my mother because she would lose her mind if she knew I’d “lost the faith.” Basically nobody in my family knows that I am not a “believer.” I moved to the other side of the country years ago and just don’t talk about religion with family so it doesn’t impact my life at all to keep it a secret.

Anyway. A family member recently asked me to be their baby’s godmother and I’m torn. I don’t think they actually expect me to help with the kid’s spiritual upbringing or whatnot. In our family being a godparent is kind of more ceremonial. I’m also a godparent to another family member but back when they were born I was extremely religious.

I feel like if I say no my entire family will know that I’m not religious and my mom’s heart will absolutely break and it will be a big thing that I would really just rather avoid. BUT doing it seems like a betrayal sort of.

What would you ladies do?