to behave in the way that you want and to not let other people influence you.
Despite being the daughter of two Hollywood stars, she's very much her own woman with her own acting style.
be (one's) own man/woman/person
To act, think, or work independently; to not accept or be swayed by outside influences. You can't just accept everything you read in the media—you have to be your own man.When I was younger, I would do anything my friends were doing, but I'm my own person now.You won't be able to manipulate her—she's really her own woman.
be your own man (or woman or person)
act independently and with confidence.
be your own ˈman/ˈwoman
act or think independently, not following others or being ordered to do things: Working for himself meant that he could be his own man.