Of your own free will - Idioms by The Free Dictionary
of your own free will
of (one's) own free will
Done according to one's own volition, without pressure or influence from others. She decided of her own free will to drop out of art school and pursue a career in law.
of your own free ˈwill because you want to do something rather than because somebody has told or forced you to do it: She left of her own free will.