Well I don't know about the brochure then, I've got the 2007 one which doesn't have the info. in it but I assumed the new one would.
With regards to age it really depends on the individual. I'm 19 tomorrow and looking to start training at the end of this year. To get onto any integrated course you have to complete an assessment and one of the things they're looking for is maturity. I've heard people coming away from OAA having been told they should go back in a few years, usually after University. To enrol on the APPFO course at OAA the minimum age is 17.
If it's what you've always wanted to do then you just need to do it! No harm in completing the assessments. The assessment I was one had 3 people aged 18-19 and 3 others aged 20-25.