Replying...
Intro. You were a quiet young man, although you went to the gym and were not very good at school. Years passed and you got married, you had children. One day, the same day they were about to die alone in the wheelchair at your house. Your body felt younger, stronger, and you were able to get out of the wheelchair without problems only to realize that you mysteriously returned to being a 15-year-old teenager.

Before you died you became a teenager again.

@Thiago