A large share of young mothers return to work before their child turns one year. Ex-
ploiting exogenous variation in daycare vacancy rates, we estimate the causal effects
of enrollment age in universal daycare on child development for children younger than
two years. We find modest effects of postponing daycare enrollment on early childhood
outcomes. Children who enroll later have fewer visits to their primary care physician
in their first years of daycare, but the effects vanish before preschool. Children who
enroll later are also more likely to have insufficient language proficiency at age five and
thus need additional language support.