You were abducted by otherworldly beings (planar, fey, fiend or celestial) Moments later, you reappear, but has physically aged 1d10+10 years, has no memories of that lost time, and has not mentally aged even a minute.
Poverty You or your family fell on hard times and were unable to pay taxes, resulting in either your character or a family member spending time in prison. Work with your DM to detirmine the details)