The first USGF national championship is held at Maine East High School in the suburbs of Chicago. Although this represented an insurrection by the college coaches against the AAU, the AAU was still the official governing body and only path to international competition. (The AAU, of course, continued to hold its own national championship. It would remain that way until 1970, when USGF replaced AAU as the official governing body. See Grossfeld 2010.)
The USGF national championship included trampoline. I have no information yet about the AAU championship. I also have no information yet about how those competitions were scored. 1963 is the first year after the FIG published the new rules with ABC difficulty as a score component, and that system may not have been used internationally yet. USGF and AAU may have written the original ABC difficulty for trampoline at this point. I am still looking for rulebooks from that time period to determine what was in them.
Grossfeld, A. (2010). A history of United States artistic gymnastics. Science of Gymnastics Journal, Vol. 2 Issue 2: 5-28