Yes, I am like you. For the longest time, I thought that "Baby I'm Burnin'" was the first disco country song, but then I saw a documentary on CMT (I think) which gave that honor to the Whisperin' Bill Anderson track.
Nothing against country artists trying to "go disco," but that song was simply an embarrassment, to both "Whisperin' Bill," and to music in general. Dolly's track was much more "believable." Of course, she had already done some crossover tunes (and would go on to do more) so recording a disco tune was much less of a "stretch" for her. With the Anderson song, it just seemed like they were "trying too hard" to record a disco country song.