Rav Mattisyahu Salomon, Shlita, is recorded on tape saying that since the main mitzvah of a woman is tznius, her entry into adulthood should be marked with tznius. A big bash is in direct contrast.
Everything should be done with Tznius. It already has a source, and is not new (but always helpful to be reminded).
Rashi Succah 49B, P’shat in the Gemorah there.