Many factors can indicate pupils’ tendencies to be interested in specific fields of study in the future. Examples of such measures are personal interests, which can also evaluate and develop institutional programmes and interventions that can support pupils’ education in computer science. In this work, we report on a study to document characteristic profiles in general interests and study interests, surveying pupil cohorts that attend different activities related to computer science: workshops (compulsory and non-compulsory) and contests related to computer science. We match these interest profiles with the interests of first-semester students of computer science. Pupils attending computer science activities in their leisure time show similar or higher interests in study fields related to studying computer science than the students, differentiating them from pupils attending compulsory workshops. We also show that the relations between general interests and study interests are uniform for pupils and students, helping teachers and syllabus builders promote encouragement towards the interest in computer science.