Pretty sure dance is a sport, but even if it isn’t, joining dance and staying committed counts as a good EC. As a freshman, you should join as many clubs are possible and then decide which you like enough to continue throughout high school.
Also join the rest of the HS Class of 2019 here: http://talk.collegeconfidential.com/high-school-life/1746601-high-school-class-of-2019.html