This paper examines the relationship between the timing of childbirth and the motherhood penalty among high-skilled Danish women. Earlier studies typically find that delaying first childbirth increases female earnings. However, postponing the first birth may also have negative fertility consequences, as it often leads to greater difficulties in conceiving. If women have their first childbirth early, before entering the labor market, this can potentially result in both positive and negative effects on their labor market outcomes. Positive effects may arise if student-mothers signal to employers that they will take up less future maternity and parental leave once they enter the labor market. Negative effects may occur if student-mothers face a delayed entry into the labor market or if they signal a preference for higher fertility compared to students without children. Using a sibling fixed effects design, we find that student-mothers have higher drop-out rates than non-student-mothers at both universities and university colleges. However, for those women completing their education, student-mothers from university colleges experience a considerably higher growth rate in earnings after labor market entry compared to non-student-mothers, and by the age of 40, they have surpassed non-student-mothers in earnings. In contrast, university student-mothers do not fully catch up with non-student-mothers by age 40, although they, on average, enter the labor market at a higher earnings level compared to non-student-mothers.