Godparents??

Okay, so this lady I work with is constantly "looking out" for me at work. She's sweet, but at times she makes me feel uncomfortable. She has never been able to have kids & never will, so she tries to take on everyone's kids. Well, after a long 12hr shift, she asked if I chose a godmom for my baby boy... tired & ready to get out the door, I said no. She then jumps to the point & asks can she be it. I jokingly say "sure" (because why would you ask if I've only known you 3 months, never been to your home, & from what she says she has a hostile marriage).... she gets extremely excited & says really! I say yea, & leave to go home thinking nothing else about it. 🙄 apparently she thought about it since. She told her husband immediately, coworkers, etc. she's my child's godmom; it's ALL she talks about during our shift & im always quiet concerning it. I seriously want to break it to her but don't know how to let her down easy. But again it's uncomfortable & makes me feel weird. & I don't want it to be any misunderstandings when he arrives. I honestly don't feel the need for godparents; my sister has taken him on as I've taken on her daughter since birth. Soooo yea! Was I wrong? What should I do in this situation? 💁🏽