Should I ask this girl to Sadies?

Okay, so I went out on a date with this girl last saturday during christmas break, and now that school is back in I've learned that the Sadies Hawkin's dance ( usually a girls-ask-guys dance ) is January 25th. I thought about asking her to the dance, but it's not very traditional to do so, so I asked some people about it, and everybody else says to except my brother (Junior, I'm a freshman). He says that if she really wanted to go out with me she would come ask me (which makes sense), but she's a very shy person so I don't know if she would even if she wanted to. What do you guys think?