That's why you get a cheap, 'well worn' bike to start out on. Not nearly as fashionable as a shiny new one, or giant chromed beast, but safer, easier to control, and better to ride until you're comfortable being on a bike and able to handle the challenges that presents.
Exactly what old, cheap bikes are FOR. already depreciated, got a few scratches and plenty of miles. Ride it for a year, learn, make your mistakes on it, and THEN get a 'real' bike. Not doing it that way is BEGGING to be hurt, or at least lose a ton of cash on a (formerly) shiny late-model bike.