This would be a good way to start. iRacing is a good community, but rookie events are rookie events everywhere. Racing with the guys here would give you a place to start where you can count on their careful racing and good sportsmanship. You'll have both this car and track, and several others. You can also buy any car and track you like and race with them on Hosted races like the league and club races here at RD.
As for iRacing itself, jump in a car (MX-5 if you like Road courses, Street Stock, maybe, if you are more interested in oval) and run the tracks you have. Then, I highly recommend the feature called spectate. This will allow you to join a practice session and watch others practice. You can learn a lot that way and the special feature is that you are asked to pick a car before spectating. You do that so if you feel like joining, you can jump in the car and drive with everyone else. BUT, you won't be visible to them, and you can't cause any wrecks! It's a great, safe way to learn to drive in close quarters.
Then, just jump into a series and start working your way up the ladder. I got to Class C so I could race Star Mazda, and I do so much racing with leagues and club events here and at another Online league that I haven't even raced a single regular iRacing event in a couple of months!