Objective This study explored whether mothers’ education magnified any benefits that waiting until older ages to have children might have for their children's educational careers. Methods Multiple‐group path modeling assessed whether and why the positive association between mothers’ age at first birth and children's test scores was greater for children of college‐educated women than children of other women. Results Older age at first birth was associated with higher math and reading test scores among the children of college‐educated women via their mothers’ higher income and cognitive support for children. These mediational paths were less pronounced among the children of high‐school‐educated women and were not observed among the children of high school dropouts. Conclusion Any potential effects of women's delayed fertility on their children's early educational experiences appeared to be confined to the most educated women.