Board Thread:Ask the Staff/@comment-4322356-20160203063031/@comment-24692230-20160203102434

Gordon Ecker wrote: It's automatic based on how long you've been active on the wiki and how many edits you've made (forum & comments section posts count as edits).

https://www.mediawiki.org/wiki/Manual:Autoconfirmed_users

I don't know the exact number are for this wiki, but your user page doesn't have a "new user" tag on it anymore, so you've already got autoconfirmed user / established registered user status here.