For a learner I would agree that a slightly heavier bike with a low seat is not such a bad thing and you’ll get used to it in no time. More stability and less flighty-ness than the lighter 125’s for sure.
However, once you get the hang of riding the CB you will probably be trying to reduce the weight in whatever way you can to improve performance.
With the smaller engines the weight of the bike makes a huge difference (that is as long as the rider doesn’t weigh more than the bike of course).