China's population has been declining by ~0.1% each year for the last 4 years.
Their median age is ~40. ~20% of the population is over 60.
And average life expectancy is ~79.

This is not very different from the USA, where median age is ~38,
~17% of the population is over 60, & average life expectancy is ~77.

What we do a bit better than the Chinese is make babies.
Chinese women on the whole are giving birth to 1.1 babies each.
American women collectively are giving birth to 1.6 babies each.
However, any nation needs its women to give birth to 2.2 babies each,
just to maintain the population.

Otherwise they will have to rely on immigration to maintain the population.
And I highly doubt anyone wants to immigrate to China,
except maybe from North Korea?