in the driver's seat
US /ɪn ðə ˈdraɪ.vɚz ˌsiːt/
UK /ɪn ðə ˈdraɪ.vɚz ˌsiːt/

1.
no controle, no comando
in control of a situation
:
•
After the merger, our company is finally in the driver's seat.
Após a fusão, nossa empresa está finalmente no controle.
•
She likes to be in the driver's seat when it comes to planning events.
Ela gosta de estar no controle quando se trata de planejar eventos.