1991 Geo Prizm SMOG PROBLEM

Engine Mechanical problem
1991 Geo Prizm 4 cyl Front Wheel Drive Automatic 32000+ miles

GOOD SUNDAY AFTERNOON, I WENT ON LAST WEEK TO HAVE SMOG TEST ONLY DONE ON MY CAR. IT DID NOT PASS, THE MECHANIC WROTE UP A RECOMMENDATION THAT I HAVE A VALVE JOB AND CATALIC CONVERTER PUT IN. SINCE SO MANY MILES IS ON THIS ENGINE, WOULD IT BE BETTER TO GET A NEW ENGINE OR RETIRE THE CAR. I LIVE IN CALIFORNIA WHERE THEY ARE VERY TUFF ON OLDER CARS. THE BODY ON THE CAR IS IN EXCELLENT CONDITION, NO DENTS. TO ME, THE ENGINE SEEMS JUST FINE. I HAVE HAD THE OIL CHANGED EVERY THREE MONTHS, THE CARD DOES NOT SMOKE OR LEAK OIL AND IT RUNS REAL QUIET WHEN I WARM IT UP EVERY MORNING. SPARK PLUGS ARE CHANGED ON A REGULAR BASIS, EVERY 6 MONTHS. I HAVE TAKEN VERY GOOD CARE OF THIS CAR. YOUR ADVICE WOULD BE VERY HELPFUL. SINCERELY ELIZABETH