Welcome young one. You have many ways to be active here.
One is browsing the Forums related to your interests.
You can also hide unwanted forums, for instance the XBOX forums if you're mostly a Nintendo Boi.
The General Off-Topic forum is good to chat about other stuff that's non game/geek related.
You might learn something on the Politics Forum.
You can share art on the Art Forum.
Write your own blog.
Comment on profile posts/threads.
And as a last chance, head over to the Edge of the Forum and post nonsense. Sometimes it's fun, sometimes you get warnings.
¯\_(ツ)_/¯