DD1 has been able to pedal from about 2 years of age. She has a bike with training wheels, and we've just raised the training wheels a little recently so she's not so dependent on them, and she's doing really well. A friend of hers who is the same age got a bike (with training wheels) for christmas and she still can't pedal. They practice with her every day, but she can't get the hang of it. All kids are different, some pick it up real quick, others don't.