My girlfriend isn't into dancing, but I wish she was
Is there a reason you want your girlfriend to like dancing?
I want someone who shares my interests.
We can't all like the same things. Expecting that your gf will like all the things that you like is unrealistic. Appreciate the things that you both do have in common and appreciate those things together.
This is important to me and I'm going to break up with her.
Breaking up with your girlfriend over this seems a bit extreme, as expecting her to like everything you do is unfair and unrealistic. It's great you love dancing and perhaps this is something you can share with your other friends while still finding common interests with your girlfriend.