Ballroom Problem !!!

Ok so here`s the deal. My parents booked my Quinceanera at a hotel where my sister works for March 7, 2009. Today we practiced in the room for the first time [it was also y first time seeing it] and it was so small !!
I dont like it at all and I want to tell my parents about how i feel but i know theyre gonna spazz out about it.
What really pisses me off is that they never talked about the size of the room but just how pretty the ceiling is. They never even took me to show me they room before depositing the money.
What should I do? Should I tell them then ask they could change the room before paying the rest of the money or just go on with it and cry evryday about it