You are an average 45 year old living with your family in Helsinki. One day, two magical gnomes show up, introduce themselves as Asila and Werdna, and give you the option to step into a portal and travel back in time to become your 16 year old self again. If you enter the portal, you immediately die once you reach age 45. You would retain the memories of your current life. You cannot ask questions, or prepare additional information to take with you. You only get this chance now, and there is no undoing either decision (staying or leaving).