D90 is a nice camera, it has absolutely everything a beginner might need... How do you like your new D7500? The specs look pretty impressive! And I guess with everyone switching to mirrorless, the "older" F-mount lenses will only get cheaper with time, especially in second hand market, so that's a huge advantage...
I'd just get a roll of B&W film for trying the old film Nikon out, it's much cheaper and I genuinely like the results better... Easy to develop at home later on too, if you get into it