Have A Mind Of One's Own Meaning
(idiomatic) To form one's personal opinions and choose one's actions without being governed by the views or choices of others; to be independently minded; to think for oneself.
Example: 1866, Bayard Taylor, The Story of Kennett, ch. 4:
"Don't be anxious, daddy!" said he, with assumed playfulness; "she's not a girl to take the first that offers. She has a mind of her own."
1874, Horatio Alger, Brave and Bold, ch. 25:
Captain Evans had a mind of his own, and did not choose to adopt any man's judgment or prejudices blindly.
1921, Louis Joseph Vance, Alias The Lone Wolf, ch. 22:
That little man has a mind of his own, and even if I do figure on his payroll as confidential secretary, he doesn't tell me everything he knows.
2003, Alison Maxwell, "How to marry your own millionaire," USA Today, 10 Feb. (retrieved 3 Nov 2010):
Be a little audacious â€” disagree on at least one thing so they know you have a mind of your own.