Every nation in the West is having this problem. No one wants to have kids. Too much work. Too expensive.
The median age in the US is 38.5 years, 61st oldest in the world. In China it is 38.4. In Japan it is 48.6. Germany 47.8. Hong Kong 45.6. South Korea 43.2. UK 40.6. Russia 40.3. Nigeria 18.6. India 28.7. Brazil 33.2. Mexico 29.3. Canada 41.8.
There is a direct correlation between how developed a country is and the median age.
Most importantly: no return on investment. Let working parents and their children opt out of paying 15% of their wages into the Demonrat's Socialist Security system, and instead require their children to pay 10% of their income to their parents in old age. That is essentially how the American Amish operate, and their fertility rate is around 6 per woman.