This project aims to expand on existing research on the use of AI tools in writing education by not only examining AI-driven pedagogical interventions and their effects but also by focusing on the learning process and potential longitudinal changes in the development of writing skills in English as a foreign language. In a preliminary step, the project provides insights into preexisting generative AI (GenAI) usage patterns and perceptions that Flemish EFL learners bring with them, thereby filling an important gap in current L2 writing research. The longitudinal project further intends to show how individual differences (such as differences in motivation and wellbeing) influence the development of writing skills and the use of GenAI, and what the effects are of using GenAI feedback on various text characteristics.