Teenage learners are a remarkable target group: they generally have a quick grasp of things and can learn particularly quickly and effectively. This is mainly due to the temporary plasticity of the adolescent brain, i.e. individual brain areas can change and specialize in the adolescent phase depending on their use.
Therefore, teenagers learn foreign languages or how to ski or play a musical instrument much qicker and with less effort. They usually can also master these things better than adult learners.
The video and study has more insight on this exciting topic.