I read that the 13th Floor Elevators did not form as a band until late 1965. Warlocks already on the scene by late spring of that year and as the Mother McCree's Uptown Jug Champs since '63. Plus Kesey's Band of Merry Pranksters was an actual group of musicians as well, forming late '63 early '64.
the 13th floor elevators where the first to be called "Psychedelic", but not the first band to be psychedelic.