That car is old now- the engine is tired- the oil pressure is low
because the oil pump is worn and some of the oil galleys may
be clogging up- but the oil pressure is probably better than zero
because the gauge is tired, too- the car is not really valuable so
you are not risking much by driving it- just go easy on it and
drive it like the old lady she is, don't rev it high or give it a lot of
gas and race it- keep the oil changed, use a higher grade oil like
50 weight, and it should still last a long time if you are careful-