"Normal" and "being normal" are just terms which describe a behaviour which is general for a certain community or society For example in many countries sleeping or eating on the floor is normal, but in other countries eating on the floor is regarded as something strange.
The same for a very simple thing like riding bike, while in the western world, riding a bike for adults is nothing strange, it's normal, but in many eastern countries only a crazy person would ride a bike, because adults are not meant to ride bikes.