I want to upgrade

I have a Pentax k-x and would like to upgrade to a newer better one what do you think is the best Pentax DSLR. I am only 13 so I would like something around 500 AUD (360 USD) or less.

Greetings Pentaxians

Hi folks. I'm new here. I use a Pentax K-3 II. I really like the Astrotracer feature for night sky work. I'm happy with my Pentax... but do ponder the mirrorless world, the older I get and arthritis setting in.