My youngest daughter Melanie is ten years younger than her brother and sister (twins). As nicknames go, she has plenty that revolve around her actual name but she was also Small Fry for years and years.
At about 10 or so, she announced that she wasn’t small anymore and needed to be called Medium Fry. OK – that’s reasonable. She could be that and the Big Kids would still be the Big Kids.
Mel is now 13. I called her into the kitchen yesterday for lunch – “Medium Fry, come get pizza.” She walked in, looked at me and said “I’m nearly as tall as you. I don’t think I can be Medium Fry anymore.” “What? Now I have to call you Large Fry? Fine, but don’t you ever ask me to call you Super Size Fry because it isn’t happening.”