Planning a trip to Atlanta. How safe is it?

I want to take my 16 year old sister & 2 friends to Atlanta. We were excited until a family friend began describing how it was when he lived there several years ago. We are from a considerably smaller place so I expect it to be different. He describes open drug deals in Six Flags, a very real possibility that my sister could be abducted, etc. I want to take this vacation but not with those risks. I doubt I'd enjoy myself for being paranoid. I'd love to be reued or cautioned by anyone living in or who has just vacationed in Atlanta. Please be serious for my peace of mind. Thank you.