19 years later is harry potter in the ministry of magic? did he achieve his ambition as an auror?

he was a boss of a auror office

Yes, he becomes the head of the auror department. Here's plus info:

link

;)
link

yup, after the seconde wizarding war, kingsely becomes head of ministry and he gives permission to thoose who fought a chance to be aurors without taking newts, so ron, harry and neville seize the opportunity and never return to hogwarts for their last an but hermione did. neville eventually retires as an auror and replaces professor sprout as a herbology professor. at the age of 27, the youngest ever, harry becomes head auror.