AO came out on February 25th, since then it’s had one content update which was the Underwater update (it included the Easter event, but that ended on may 23rd). The upcoming potion & brewing will hopefully release within the next few weeks, which introduces a whole bunch of potion types into the game (you can check out this post for more information on potions). After that update we can look forward to stuff like the Dark Sea.
Overall you really haven’t missed much (outside of the Easter Event if you care about seasonals), after a few days or weeks of playing the game you’ll be at the same place as everyone else currently is. AO’s still technically in early access though, so even if you put off playing the game for a while longer you still wouldn’t be too far behind once you decide to pic it up. If you need help with anything or have any questions once u start playing, you can check out the help centre post for basically anything AO related. Enjoy!