Good advice! Although if I was the subject, I’d be more comfortable with a photographer at telephoto distance. We may come out of this Covid thing with everyone being more comfortable with a further-out personal distance — but that’s a different topic.

The major reason that 80+mm is considered a portrait length is that a longer-than-normal lens makes it easy to separate your subject from the background using depth of field — and the longer the lens the shorter the DoF for any particular aperture. BUT you can create that same separation with a shorter lens. Open the aperture wider, or greater distance from subject to background. Don’t use up your subject’s time with this — go out and experiment with the gear you have. Look at the DoF charts — you may need to focus in front of your subject. If you still have issues making the background go soft, you might need a faster lens.

Nikon specific (skip if that’s not you): If you have an F-mount Nikon (pretty much all of ’em- even their Z series have an adapter available), the 50mm f/1.8 D series lens is cheap, the f/1.4 version only a bit more. There’s a comparison of these, plus the newer G series lens here. TLDR: the 1.4 D is worth the ~60 bucks more. Also: for the APS-C (Dnnnn and D500) bodies, 50mm is a portrait lens, but beware: the D lenses don’t have built in AF motors, so you’d need a body with an AF motor. Some do: D500, D7000-D7200).

Aand… if you’re not trying to separate the subject and background (AKA an ‘environmental’ portrait) then none of this matters.

Disclaimer: I’m primarily a landscape guy — but I’ll do portraits if someone asks really nicely. And I’m an amateur — I have no intention of spoiling my hobby, but, again, that’s a different topic.