Not encountered as a first language perhaps, but that is just incidental to your experience and has little to do with age. It is true that before home computers were widely available, one's first exposure to a computer language was likely to be from college, university or work, and there was a fair chance that that language would be Fortran.
I think you are correct about the ZX-81 and the VIC-20, those machines were somewhat restricted in what they could do. Nevertheless, the C-64 had at least Abacus Fortran and ABSoft had it for the Amiga. Microsoft and Watcom had Fortran for DOS.
Now, Windows based PCs.. that's just for gaming ;) Just kidding - there is a multitude of them, including GNU Gfortran.
Sadly, unlike the VIC-20, ZX-81, C-64s of the time, PCs sold today to not even boot into an environment with a programming language, but that can be fixed by installing Linux or BSD.