What do you think?? Help?!😂💔😩

So I'm in the 7th Grade and at the end of the year we're having a formal, to celebrate our passing through to the next grade and doing well throughout the year.

The theme is a Masquerade Ball(they just want us to wear a cute little mask), but our actual clothing needs to be black, white or both.

I went on Superbalist and found this cute little black dress, but I don't know whether or not I should get it.

What do you think?

BTW I'm 5,6 and have a hourglass type figure and I have a flat stomach (no shade on those who don't, not meant to be mean or hurtful)

This is not me, it's the model duhh😂💔

And what type and colour shoe and mask would go with it? And lastly should I wear my hair up or down?