Many parents return to work, placing their child in nonparental care before the age of one. Using variations in daycare vacancy rates, we estimate the causal effects of enrollment age in universal daycare on child development. In general, we find no evidence that earlier enrollment harms early child development, except for a temporary health shock. Children who enter later initially have fewer primary care visits, but the effects fade in preschool. Conversely, the results suggest some positive effects of early enrollment. Children who enter daycare later are more likely to demonstrate inadequate language skills by age five, particularly among boys.