Moving from a balance bike to pedals means pedalling, steering and balancing together. Even a confident balance-bike rider is still a beginner at this stage. Experience therefore matters when choosing the size.
With a suitable fit, the child can sit comfortably and put both feet on the ground. Buying an oversized bicycle to grow into makes those first rides harder.
Illustration: a child and parent try the fit of a first pedal bicycle.
Check whether the child can easily reach and squeeze the brake levers. A lightweight bicycle is easier to push and move around. If possible, arrange a short ride before buying.