Not Really

Good morning, and happy September! But why is it September? Why did we decide on months? Why not Gargalides to tell what time of year it is? It could be Gargalide Three if you wanted it to be. Is it really September? Things are not always what they seem - Sometimes you think everything around you is changing, although, really, you are the one changing.
A poem that I have written about this strange matter itself, here is "Not Really":

Not Really
The crisp is not so crisp
The grass is not so green
Is the air more than just a wisp?
Well, not really.
The ripple isn't water
The mist is more than air
Are the pages getting longer?
Well, not really.

However, there is a certain reason it is September. Just saying.