I had to have been about 4 when I got this 2nd-hand cruiser, 16" wheels, full fenders, brush-painted light blue, and about a million stickers on the fenders. Didn't have training wheels; I promptly crashed, cried, and wanted nothing to with it, not even after seeing my dad ride it perfectly straight down gramma's sidewalk. But with training wheels, I was on it.
Once, a training wheel collapsed, and I wiped out. Cried again.
I don't remember if I ever rode that bike without the training wheels; I must have, though, because my next bike -- 20" Schwinn Stingray -- was training-wheel-free, and I never had a bit of trouble with it.
That was so long ago -- before the family got its first color tv -- that my MEMORY is largely black-and-white (except for the blue paint, of course).