"When I were a lad",
In the 50s, before gaps between training courses, holding postings & leave had been invented, things were a little quicker. Having joined the RAF in September 1954 I was declared "Operational" (Combat Ready?) in January 1957 at 20½ years old. Training included flying the Hunter F1 (no T7 yet) for the first time on my 20th birthday at Pembrey, nice present from my Flight Commander!