Not really an expert in this particular area, but the research I'm aware of kind of suggests if anything the opposite is true, depending on what you mean by "the ability to learn new things."
There's some cognitive decline, but it tends to start after 25 or so, and it's mostly associated with slowed speed per se rather than learning ability. There's also some controversy in that the declines might be associated with serious health conditions, that are associated with age, rather than age per se.
The other things you mention either stay the same or increase with age, which strikes people as kind of counter-intuitive, which speaks to stereotypes people have.
There's some cognitive decline, but it tends to start after 25 or so, and it's mostly associated with slowed speed per se rather than learning ability. There's also some controversy in that the declines might be associated with serious health conditions, that are associated with age, rather than age per se.
The other things you mention either stay the same or increase with age, which strikes people as kind of counter-intuitive, which speaks to stereotypes people have.