Sato started racing when he was 19 and he's probably the second best japanese driver only to Kobayashi (also has a podium like Koby). It's not too late to get into racing, it might be pretty late for you to get into F1 however but you never know...
Jim Russell is a great school but if you have no interest in American based motorsports (IndyCar and Grand-Am) then it might not be a good idea to go stateside.
With open wheel, IndyCar's pretty much within it's own world like Formula Nippon, but Grand-Am crosses over with WEC and GT drivers all the time as the endurance sports car world is less... well... mutually exclusive (a light schedule tends to help with that too).
Also you might want to look into the background of Fairuz Fauzy. He didn't exactly "make it" into F1 (as he never got a drive) but he came pretty close. Honestly, if you want to get into racing it might be a better shot with tin tops than formulas.
Also... people will probably scoff at this... but simulations (like PROPER simulations like Live for Speed, iRacing, rFactor 2 not arcadey wannabie sims) can actually help a lot in understanding basic car control. How well simulator experience translates into real life experience will depend on the person but I say that the fact that Greger Huttu or Wyatt Gooden can be somewhat decent in real life without any pre existing experience speaks a lot to games like iRacing. Read this:
http://kotaku.com/5700609/can-a-video-g ... ace-driver