I suggest you get a corolla or a civic. Maybe an AE90 to AE111 corolla. Or an EF/EG/EK/ES/FD civic. Coz of availability of aftermarket parts and spares. Don't modify in bulk, just modify the car as you go along.
Most people either start from street/drag racing, some start from karting. But i guess if you wanna really be good, then start with karting. If you wanna learn from events, try doing Autocross or join any Run What You Brung event.