A potent conjunction of the stars and planets occurs on your birthday. you are struck by a falling star which passes through your body like it was made of mist. you awaken feeling different, as if something has been awakened from within.
Martial training: In adolescence you trained with the weapons of your people and learnt how to use them proficiently (work with your DM to determine details)
In adulthood you have an encounter with an unusual person, who as far as you can tell, has no home or family. You offer to help in anyway you can. After accepting your hospitality the stranger vanishes leaving a note "Your kindness will be remembered".