yep, agree it's more 70s influenced than 50s, but, it could in fact be from the 80s and 90s when retro restaurant/diners were the rage.
at The Hard Rock Cafe (the first one opened in 1971), we wore white uniforms that looked like vintage waitress/nurse outfits, with a white apron, and even a little white headband/hat. (ours were all white)
There were also restaurants that when certain songs came on, the servers jumped on the bar and/or counter-tops and would dance a routine: I don't recall the name of the restaurant, but their uniforms were diner-looking as well. That was in the late 80s/early 90s.
yours is cute! love the gingham look buttons!