Smaller bikes can be fun, especially if they're light. However, it also depends on how tall/big you are. A big tall guy on a small bike might look somewhat comical, not to mention possibly uncomfortable. Best would be to test ride all the bikes on your list, alas, many dealers will be hesitant to give a new bike test ride to someone who just got their motorcycle license "yesterday," so you are kind of buying blind. And that's another reason why your first bike should be a used bike. Even if the seller does not allow you to test ride, and you end up not happy with the bike, you can always sell it for pretty much what you paid for it. On the other hand, if you quickly sell a bike that was bought new, you will lose quite a bit.
Then, after a year or two of riding used stuff, new bike dealers will have no problem with you test riding new bikes.