I suggest that you drop the 'racing' part and focus on track 'driving' instead.
Sorry if that sounds a bit sarcastic. Get out to the track by all means. it's one of the most rewarding things you can do as an enthusiast.
I'm pretty confident that you'll be much more satisfied (and richer) in the long run if you stay focused on 'racing' in the sense of competing against yourself from the outset, as opposed to worrying about 'racing' in terms of chasing down other cars on the track (which leads down a huge huge rabbit hole of expenditures on mods).
Go for it!