I was stationed with Jill at a former base and was in the same career field as she is. She is a personnelist. In the AF, we take 4 years to Capt, and about 5.5-6 years to Major (from Capt). There are TONS of young 30's Majors out there. Her promotion rate was completely normal ("in the zone").
Meant to add that my son was Army. Chose infantry. Served four years in Germany and came out of the military when my husband became critcally ill.