I am over 65 and would be a candidate for a booster going by this, but..... My initial dose of the vaccine, plus the second dose, was Moderna. I'm not too keen on the idea of mixing up the vaccines and being injected now with Pfizer at this point. Maybe soon Moderna will also be officially approved and therefore made available for boosters as well..... ?
I'd wait for the Moderna triple-variant booster myself.