That is ageist. His age is not the issue. His cognitive strength is what matters. And, he's sharp as a tack. The US economy is the strongest in the world. Biden saved our pandemic ravaged economy and has begun to swell the middle class again -- which had been shrinking rapidly under Trump. We saw more shrinkage of the middle class under Trump's four years than in the eight years of Reagan.
If we have to watch Trump burn it all down, it will be because of ageists and those who swallow the GOP lies about the economy and immigration at the southern border.
Your points against Biden are Republican talking points.