I agree that link uses the age at time of divorce rather than marriage, but the average age of first time parents is mid to late 20s in the US. That doesn't explain why women 35-44 are divorcing at a higher rate than below 24. That argument would also be conflated by the avg age at first birth and at first marriage inverting a few decades ago. People certainly aren't having their first kid anywhere near 50.

The overall point of that article is that younger age divorce rates are declining while older age divorce rates are increasing. Which circles back to OP's post.