If I taught dance at a studio and worked as a ticketing services manager at a non-profit performing arts center, earning under 12k, am I a"Qualified Performing Artist"?

No - You are not considered a performer.  The IRS defines a qualified performing artist (QPA)as an individual who:

1. Performed services in the performing arts as an employee for at least two employers during the year,
2. Received from at least two of those employers wages of $200 or more per employer,
3. Had allowable business expenses attributable to the performing arts of more than 10% of gross income from the performing arts, and
4. AGI is $16,000 or less before deducting expenses as a performing artist.

In any event, the only advantage to being considered a QPA is that you can deduct your performing-arts-related business expenses whether or not you itemize.