Let (one) have (one's) head verb phrase
Give someone more freedom or allow them to do what they want
Her parents promise to let her have her head when she turns 18.
The teacher lets the students have their heads and allow them to choose their own teammates.
My parents let me have my head on my future career.
They won't let us have our heads.
Someone gives you a lot of freedom or you're not under someone else's control.
The verb "let" should be conjugated according to its tense.