Gym Etiquette? Rules?

So I was heading to Turbokick today, and I couldn’t figure out what I wanted to do with my hair, my hair!  Like it’s not enough that I already worry about what I should be wearing to the gym or Zumba, or rugby practice.  I add worrying about my hair to the mix.  Here’s what I was thinking.  “Does this side ponytail make me seem like an amateur gym goer?” You know? Like girls who work out with their hair down – which is one of my pet peeves.
This question led me to Google. “No problem,” I thought to myself.  The girls of the internet will help me with this one.  Dear Google, “Is it okay to wear a side ponytail to an aerobics class?” But alas, Google might as well have said, “Hannah, the internet does not care about proper gym etiquette.” Nope, the only thing the interwebs had to say about sideponytails had to do with the 80s aerobics ladies in bright pink spandex and corny background music.
So I decided I was going to do it; my hair always ends up all in my face anyway.  I might as well prolong the cuteness of my little hair style I found on some blog.  Then, I wondered what the hell I was going to wear to the gym.  I don’t have any yoga pants for gosh sake!  Finally, I decided that it does not matter at all what I wear to the gym; I’m not there for anyone else but me.  Screw those crazy ladies who’d judge my workout clothes!

X All the Things 
Sidenote: Turbokick was not happening today, so I had to get on some gross machine and watch Buffy instead. Also, I’m pretty sure I’ve looked something like this up on the internet before.  Isn’t there some sort of guide to being a girl by someone, somewhere?
I’m sure there is.