It reminds me of a slightly longer, navy Merino wool version from Hobbs which had small kick pleats at the back which I wore with a matching short, fitted cardigan jacket. That must have been late 1990s early 2000s ?
I still have jacket. Skirt stopped fitting a while back. I got so much wear out of them.
I can't begin to imagine how you think it might be too young for you. (Or that Hobbs these days would have a pure Merino version)