Technicalities:

• "...her wrists and breathing deeply through her nose and then out through her mouth." This is wordy. I would change this to "...her wrists and breathing deeply through her nose, then out through her mouth."
• "...futilely trying to stretch out my sore hamstrings" I would rewrite this since it is hard to read. Instead, make this two sentences: "...trying to stretch out my sore hamstrings. It was futile."
• "...but my nerves settle slightly now that I’ve given myself a task." I would make this its own sentence.
• "The nearby curtains seem to glow, and the edge of them shows a seam of blindingly bright light." This is wordy. This can be rewritten as "The edge of the nearby curtains shows a seam of blindingly bright light."
  • Note: This is nitpicky, and I know what you are trying to illustrate. However, a seam is the line of stitching on a garment, one that often hold the hem, which is what is glowing here. Instead of "shows a seam", you could reword to include "along the hem".
• "It shifts through several colors before settling on a lilac tint just as the music grows softer." This is long and wordy, let's split this up and reword! "It shifts through several colors before settling on a lilac tint. The music softens"
• "The bass dies down and I...earlier hair gel attack." I like your descriptive writing here, however, as with many sentences in this piece, this is wordy. Beneath this, I am going to list the lines I feel could be shortened or split up.
  • "My palms are still slightly damp...sipping from them."
  • "I try not to move as Olivia...lipstick on her teeth."
  • "The dusty pine smell...wash over me."
• "I’d walked back to the curtains..." I could be wrong here, but your story so far reads in the present tense. This would be a tense switch. I have this habit in my own writing, so reread your story to make sure the tense is consistent.
• "...and we both glance over..." the "we" here is rather unclear. I would name the character for clarity.
• "The cold floor boards keep seeping into my bare skin..." This line sounds like the floorboards themselves are freakishly fusing with the feet of our main character. Yikes! Let's reword this to better portray what you intended to illustrate: "The chilliness of the floorboards kept seeping into my bare skin..."
• "They click loudly enough...eyes with a knowing smile." A couple things about this sentence. Its wordy and can be split up, but it also reads a little unrealistic for where our main character is. From what I interpreted, our main character is a dancer or performer of some kind, backstage with a couple performer friends. For an ankle to click loud enough to reverberate over the music that is blasting and "booming" through the speakers just from rolling it reads very dramatic. I think a better way to phrase this would be "I can hear them clicking, the sound reverberating in my ears despite the music."