I’m sure that’s right.I’m much older, and my first language is metric but I have conversational imperial. There won’t be many people under 60 who weren’t taught exclusively in metric.
I’m 64 and I was taught, for example, 1,760 yards in a mile, although chains only came along with my railway interest.
My brother is two years younger than me, and I’m pretty sure he doesn’t have a clue about imperial measures.

