Can I take dance classes even if i’m not a dance major

Yes, of course! Many schools provide extracurricular activities, including dance; There may be a dance club, dance team, etc. There is also the option of minoring in dance.

As long as it doesn’t take away from any classes that will further your future career i don't see why not. Especially if you can take it in place of a gym class you definitely should. Just because something doesn’t further your career it doesn’t mean you can’t do it. You’re still in high school, have fun! Plus on college apps I’m sure it will show personality and they’ll like that you did something you're interested in. I’m also a high school student so I cant say anything for sure. But very few people are dance majors but plenty of people take dance. I think you should take that dance class!