I say, and that's my opinion, don't go for the fast car. Try to take it step by step. I'm new to iracing too and i'm quit fast in the mazda. But i also like the mazda. If you're interested in iRacing because of the somewhat realistic side of it, more simulator than game, than it's a great experience to learn to heel&toe, throttle match, trailbrake, ... I own faster cars like the McLaren & RUF which are very fun to drive. Especially the Ruf C-spec in the world sports car series were there's no abs or TC option. But i'm not doing official race events because i wan't to be fast (or 90% as fast as possible for me) and consistant in those cars first. (they are a handfull but very rewarding if you "got it right")
I switched to the advanced mazda's after i while. (Still mx-5, but with open setup) Now i start to really anjoy the community part of the sim. And also the very helpfulness of the fastest guys and even the aliens. Nowhere can an in-game community be found that takes it as serious as you want or is a friendly as it gets. I learned from others as much as i learned on my own in iRacing. And the "others" were even happy to help. Not really happening in other games so much i think.
So (still only my pov), stick to a slow car, learn the tracks / behaviors / ... you'll also start to learn to know some of the guys you started with and eventually the experienced and faster guys. And the occupation question; If you're European than you're good in iRacing. Don't expect the same amount of online "rooms" like say a "Gran Turismo". Do expect stability and a far far greater experience if you're using a wheel / rig.
If you decide to go iRacing and want some on track advice, just ask me or pm me (my iracing name is Dries Nys2)
See ya