Old looking boobs?

I was sexting someone and I sent them a picture of my boobs. I’m 18 with 2 kids, both breastfed. They asked me again what my age was and I repeated to them that I was 18. They told me they refused to believe that my boobs belonged to an 18 year old and stopped replying to my messages. I just want to know why. Was is the shape of my boobs or the nipples? Or was it just everything all together? I’m not hurt. I’m not everyone’s type and I accept that, but it was so funny I just turned my vibrator off and laughed about it the rest of the night. 🤣