Timing Matters: Age of Onset in Online Child Sexual Solicitation and Abuse and Young Adults’ Well-Being

<title>Abstract</title> <p> Online child sexual solicitation and abuse (OCSSA) is a widespread phenomenon with first exposure clustering in adolescence. While accumulating evidence documents adverse psychological correlates, the role of developmental timing across the spectrum of OCSSA subtypes remains poorly understood. Data were drawn from a nationally representative German survey of <italic>N</italic>  = 1,006 young adults aged 18 to 29 years. Nine OCSSA subtypes and age at first exposure were assessed retrospectively and operationalized as single-year onset indicators. Psychological well-being was measured using the WHO-5 Well-Being Index. A dual machine learning approach combining LASSO and Random Forest regression was used to identify robust predictors, controlling for offline CM, age, gender, education, and equivalized household income. A post-hoc multiple linear regression provided interpretable effect estimates. 32.3% of participants reported at least one form of OCSSA before age 18. Offline CM was the dominant predictor of reduced well-being ( <italic>B</italic> = − 17.66, <italic>p</italic> &lt; .001). Three age of OCSSA onset predictors were identified: unwanted exposure to pornographic/sexualized material at ages 13 and 15, and unwanted sexualized talk at age 15. Of these, exposure to pornographic/sexualized material at age 13 remained statistically significant in the post-hoc regression ( <italic>B</italic> = − 11.22, <italic>p</italic> = .005). Specific OCSSA subtypes at particular ages may relate to long-term well-being, with early-to-mid adolescence emerging as a potentially sensitive developmental period. </p>