Reading your comments after this poem lets me know what you were trying to achieve and that helps a lot with writing critiques and the like.
So many don't bother with them and its annoying

The fact that its meant for girls who think looks is the key to the be all and end all for finding a partner is a very interesting choice for a poem and pretty original.
It was always going to be a tough 1 to nail on so lets go through it shall we...

When we are young its all about looks. Always has been, and always will be. It is pathetic tbh but, at school people get bullied and singled out for what they wear, look like, who they date and so forth.
Only a very rare few will actually stand up and hold there head high and be themselves but that is the curse of youth unfortunately.
Also noted that when I was going through my school years I knew many girls liked me but cause of who I was they never dared for sake of looking like an outcast... and now am older its them who are sorry and not me

But anyhow to the poem
The opening line is nice and instantly calls for attention, its also the same way that you've made the people in question come across too.
With this the beginning of the piece flows very well and smooth, my only call of pause is where you have put and using a word such as with for example will help the flow more I feel.

Curves and lines
with shapes that I
won't mention

The should you be listening part is nice and isolated letting us know that your not even that bothered at this time, I do feel though that using Italics here is more than sufficient without needing the extra brackets.

Its pretty easy to see what your after here though I do wonder at the wording towards the end.
You mention to them to stop the cheek, to stop pretending and to start amusing, I presume, you.
Is this a way for them to catch your eye or are you meaning that they are amusing you with this?

I struggle to work out that meaning.
Same with the final block here, I feel that if you were to word it slightly differently you'd make more of an impact with the words but, to me, it does die off a bit towards the end.
If I was to write this myself I would probably do it like this:

So stop the cheek,
and quit masquerading your love
while my amusement gathers

You start to speak,
and just make me laugh
whilst failing at seduction.

Remember your trying to make a statement here with your words as much as you are a Free verse poem. Your original words do feel a bit confused towards the end and I was struggling to put them in order, the above is just an example and I'm not trying to tell you what is better or what is not, as at end of the day it is your work and not mine.

The intention is there though and so is the meaning. But for wither it comes across or not, I feel it comes across with relation to YOU specifically, rather than girls on a whole.
It was an original and difficult task you set yourself but you have done well and it is a good read

This Critique was under taken from
I hope this Critique is fair in your eyes and I have written this as honestly as I possibly can.
If there is anything you want to discuss then feel free to contract myself