Welcome to dA, fellow introvert! I hope you enjoy your stay here--it's been a few months since I joined, and I'm having a grand old time.
I see you haven't joined any groups yet--I'm pretty introverted myself, and yet the best part of groups is often just being exposed to other people's art for a specific fandom, medium, etc. And if you're feeling brave, you can submit your own art as well! I highly recommend it--but like, you do you, man. However you choose to enjoy this website, I hope that it brings you joy on your art journey.
Cheers! <3