Proper translation of "dancer"?
If you are serious, I don't think any word like 舞娘 or 尬舞 is a good choice. (Probably 舞娘 is from the song by Jolin Tsai.) 舞蹈家 is a title for professional and experienced dancers. I don't know if your friend could be called a 舞蹈家, so if yes, just go with 舞蹈家. But 舞者 would always be a good translation.