I am a total believer in "balance" bikes. Luke rode one around for several months and when it was time for the "big" bike, he immediately took off with almost no help--just a hand on his back for confidence.
I'm old. Granted, I was old when he was born. But, my baby is no longer a baby. He is a very capable, imaginative, confident, bike-riding, little boy!
Kindergarten, here we come! (Best wishes to his teacher!)