We can't just look at fertility rate by age cohort. We also have to look at the percentage of population that is in that age cohort, to determine impact.
Most people in the US are white, and most white people are old. The most common age for a white US person is ~58.🤷🏿♂️
The chart you shared above shows that the birth rate for women aged 30 to 39 was increasing slightly. The chart below shows that women aged 30 to 39 account for 45.9% of all live births in the US