niche: how narrow is narrow enough?

my niche so far is educated women (i picture women aged 28-35) who want to tune into their bodies so they can lose weight and keep it off. is this narrow enough?

my personal goal is to eat vegan+gluten free so i thought of adding that to narrow my niche, but i seriously know zero people who want to be that, let alone would PAY to be that. and i’m still navigating this journey myself, so i feel

but then i watched one of the entrepreneur q&a calls and brooke explained something along the lines of: what you know now isn’t what will get your there (to goal), which is why we don’t need to know the “how” for our businesses.

so then the question: does this idea about people not wanting to pay for help to lose weight via a vegan+gf diet sound more like a limiting belief? and/or is my initial niche narrow enough…
*side note: i literally just realized that this exact thing that i’m questioning (people being willing to pay to manage their minds around becoming vegan/gluten free) is the exact thing that i started paying brooke for, ha! i literally joined self-coaching scholars to help me figure out why i haven’t been able to give up meat, dairy, and gluten. but i still feel like i’m an exception because i know no one else who is doing or wants to do this. so back to my question…. as you can see i’m a little stuck in this cycle.