After my son took an interest in riding, my daughter did not want to be left out.

She wasn't quite as fast, but she learned it pretty quick.  After a few spills, our neighbor suggested learning to ride a slight grassy slope behind her house.

After a few runs, she had the confidence to hit the street again the next day.

What I find amazing is how different my two kids are.  My son learned to ride his bike 2 1/2 years (by age) before his older sister.  But in contrast, my daughter was dressing herself (multiple times per day) a few years before my son did.  To prove my point, my daughter's first comment when she got her tricycle was that it matched her red dress.  Watch the video.