shima-draws answered:

YELL HEAH definitely watch season 3! It slaps! It’s so unbelievably good!

If you’ve seen the end of GGO you should be fine! I do recommend finishing off season 2 because there’s two really great arcs that wrap up the season (Calibur arc is really fun and lighthearted and is a nice break from the drama, and Klein gets to have the spotlight for a bit which I love bc he’s such a great character. And then the Zekken arc will RIP your heart out trust me it’s so sad but it’s so good.) Either way you don’t HAVE to finish season 2 in order to start season 3–as long as you still remember the general plot of GGO you should be fine, because they kinda talk about the aftermath of that in the first episode with Sinon and all. But yeah you can jump right in!