in front of you; ahead of you
Tu as toute ta vie devant toi.
You have your whole life ahead of you.
Amuse-toi bien, tu as la vie devant toi.
Have fun, you have your whole life ahead of you.
Qu'est-ce qu'il y a devant toi ?
What's in front of you?
I am in front of you.
Tu as toute la vie devant toi.
You have your whole life ahead of you.
Tu as devant toi le roi de Laputa.
You have before you the king of Laputa.
— Le Château dans le ciel (1986)
You have your whole life ahead of you.