In this study, we compare students' ability to learn and master a variety of computer programming concepts in two different student groups. The first group consists of 64 university level students with various backgrounds (adult control), and the second group consists of 40 Finnish junior high school students of age 15 (adolescent treatment group). Neither group had significant prior programming experience. Both groups were taught a similar semester-long introductory course on Python programming, using the same learning management system (LMS). We find that for almost all of the concepts, both groups perform equally well, but students in the adolescent treatment group perform significantly worse when learning the concepts of loop structures and repetition. The results are further compared to the lecture surveys that were collected from the junior high school course to further explain the causes of the findings. Based on the results and the teaching methods that are presented in this paper, we are able to show that adolescent junior high school students and adult university students have similar abilities to learn abstract computer science concepts using a fully functional programming environment.