Ha, this hits home. I started my consultancy practice when I was 23 - but looked about 15. So growing some stubble was part of the plan. I think there's a lot to be said about authenticity - I definitely get your point there. I also think sometimes you just need to embrace the tactics which work you've outlined here.

I remember embracing similar things. Speaking with intent, being clear, concise, and direct. Getting comfortable taking the most prestigious chair in the room etc....Over time it just becomes more natural.