I spent 5 years enlisted, then went to college and OCS. I was commissioned after 2 years of college in the reserves at age 23. But what your father did is normal. I knew a Master Sergeant (E8) who attended OCS and was a 2nd Lieutenant at age 32. That is rare. I retired at age 39 as a Captain (O3). I had a guy in my OCS class who was commissioned at age 19, but turned 20 a month later. That also is rare. He went to college and joined the guard right after HS. After one year, you can attend OCS, which is what he did. On another note, he was probably one of the worst Lieutenants to come out of our class due to his immaturity. There is a big difference between an 18 year old and 23 year old.