Creatures created with True Polymorph: Aging

I was wondering what would be your take on the following situation:

Wizard creates a dragon with True Polymorph.

1 - Would it age and grow as a normal dragon?

2 - As it was made with magic, would it survive the if the caster who created it dies?

3 - Other than Wish, how you guys would suggest an in-game mechanic or narritive manner to make the creatures existence more permanent (meaning not simply easily dispellable by an Anti-magic Field and the works)

Thanks in advance.