The text usually only ever gives vague "it's really big" descriptions and has only explicitly stated the size in a specific numerical sense as 10 inches as far as I remember. Also she doesn't need to care much about your dick anyway since she's more interested in what you can do for hers.
I don't think pc and npc descriptions should be compared 1 to 1. Since some npc descriptions are set and the pc's are like randomly chosen from a list for various size ranges. And huge is subjective anyway.
Aww that's a shame. She's so dommy I was hoping it was massive.
My initial gist was it being somewhere between 14-18.
I'll just cross my fingers and hope for tfs. If someone is going to bully me for my tiny penis they damn well better be able to cockslap me unconscious with theirs.