Why South Korea's birth rate is expected to plummet even further

The age for late-age pregnancy is physically fixed and cannot be changed.
For those in their mid-to-late 30s, in 3 to 5 years, even getting pregnant will become extremely difficult, and the probability of birth defects will skyrocket.
Furthermore, looking strictly at the population numbers of those in their teens and 20s, the teenage population is currently only two-thirds of the population in their 30s.
Even if the birth rate were to remain constant, the number of births would drop to two-thirds of current levels, and the unmarried rate is only set to continue rising.
Because the ladder to real estate ownership has been kicked away,
I expect the birth rate in 10 years (2035–2040) to be around 0.5, with the number of annual births falling to about 100,000–120,000, which is roughly 40% of current levels.