I'd go with an EX-500 or SV-650. If it's gonna be your only bike the SV is better on the street. When you get tired of race prepping your street bike, the SV will serve either purpose well.
Both bike's are competitive under competent riders, check out last years
LRRS race results
Don't even think about contaminating your ability and potential with fear of your age, that goes if your 20, 30, or 70. However, since you don't ride now, take all those courses and race clinics that you mentioned, it'll keep the learning curve nice and steep.
No matter what you ride, a bike can't make you fast if you're not.
If in the end, you don't have the passion for racing you thought you might have, then an SV-650 is still a great street & track bike...
Good luck,
-Jack