The experience of the first intercourse at an early age is a well-established sexual risk behavior as it is related to adverse physical and mental health outcomes. However, the diversity within the group of early starters as well as the actual processes that make early first-time intercourse (potentially) more harmful remain understudied. The goal of this research is to understand the mechanisms that make an early experience of the first intercourse either more or less emotionally harmful. Therefore, a combination of quantitative and qualitative data are used. The quantitative data stem from a population survey (ages 14-35 years; N = 705); the qualitative data were gathered by in-depth interviews among 24 young people (ages 16-18 years) with an early first-time intercourse (at age 14 years or younger). Quantitative analyses show that the age at first-time intercourse is positively related to the feeling of readiness. For the male respondents only, it is also positively related to the general experience of the first intercourse. For female respondents, the age at the first intercourse is only related to the general experience of it in interaction with the age difference with the first partner. Qualitative analyses show that much variation goes behind these statistical regularities. Successful early starters can be differentiated from problematic early starters based on relationship characteristics, the preceding sexual trajectory, and the preceding sexual decision making. Practical implications are described, and recommendations for further research are made.