What MY? Mileage? What is the full DTC?
FWIIW, the odds do not favor the O2 sensor being bad. More likely a bad cat. There is a saying that cats do not die. They are murdered. Meaning that cats will usually last the lifetime of the car. But when they fail, it is usually something external to the cat causing the cat to go bad.
Depending upon the MY, suspect a bad head gasket allowing oil or anti-freeze to contaminate the exhaust.
You might get lucky and the O2 sensor is bad. And then again, maybe the all the "nasty" video girls really are just 18 and it really is their "first time".