You should still keep doing the bottom-up approach for the rest of the docs. Just update the README first paragraph or two as the gp says.

Yes, strong agree, normalcy resumes at some point. But you want the hook in first.

I mean, I'm phrasing that in marketing terms, but in this case it's in harmony with what your users want anyhow. We want to know ASAP why we should care about this language. So it works for everyone. Of course when it comes time to deliver the promise, normal programming language documentation is the way it is for a reason.