[Grammar] GROW UP

[shibli.aftab]

When can I drive the car?

Which should be the correct answer from below written sentences? If both are possible, then what is the difference in meaning between both sentences?

1. When you grow up.
2. When you are grown up.

 

[Raymott]

1. is better because because it's simple. 2 is not wrong, though.

 

[Rover_KE]

There are many other possible answers.

'When you have passed your driving test.'

'When you start contributing to its maintenance.'

 

[tzfujimino]

Or 'when you're grown-up [adjective]' or 'when you've grown up [the present perfect]'

 

[shibli.aftab]

There are many other possible answers.

'When you have passed your driving test.'

'When you start contributing to its maintenance.'

Is it correct to say,
'When you will have passed your driving test.'

'When you will start contributing to its maintenance.'? If it is incorrect then please explain why.