welcome, i'd start off just doing demo races until you find your feet and feel that you're somewhat competitive and comfortable on track.
once you're comfortable with xfg/xrg, maybe try fragmasters GTi thursday, or MRc FBM saturday (another demo car), 60 and 50 minute races respectively each week on different tracks.
being around 20+ cars on track can be intimidating, but as long as you're not wildly off pace and safe on track, you should be fine, pace will come over time.