AITA for no longer being available

First off I just want to say I’ve never done one of these before and I don’t know what to expect. i would be so delighted if I see charlotte reading this. Love her chanel. Sorry, so to start off, I (33f) have these 2 friends who are married let’s call my closest friend (31m) Sam and his wife (24f) Linda. Now I’ve known Sam for 8 almost 9 years because I dated his best friend. when me and his bf broke up we stayed friends and have always been there like a sister. Now to get to the main event, his wife is 34 weeks pregnant and Sam is the Godfather to my daughter. I was under the impression that I would be the godmother to their soon to be daughter. Linda and I went for breakfast and I made a comment about if they decided I would be a godmother, I would be called Auntie. she looked at me and said that they were talking about that and decided I would not be the godmother but instead be someone else, now mind you it’s someone who they havent known as long as myself. Now I dont mind them choosing whoever they want as a godparent even if it’s not me. I told her that was ok and just wanted to know why, because I’m curious and would feel better if I no why. she proceeds to tell me it’s because they don’t think I’m reliable enough and went with someone who to them is more reliable. I was stunned, every time they needed anything, I was always the first person they called and always showed up when they needed something, and as soon as she says this to me, the person they deemed more reliable, calls and asks if we can come help him. I looked at her and said so he’s more reliable than me? After that I decided I’m done. If you need something or someone to help with whatever, ask the one y’all chose who is reliable. cuz apparently it’s not me so I will no longer be available when you need something. Do y’all think im overreacting about this or am I overthinking it or aita if I remove myself entirely? Any advice helps.