My son did his PPL while in Year 12 in 2012 and it worked out fine.
In Victoria you can do Aviation as a "VET" subject that counts towards you VCE result. If you complete a CPL at the same time you get extra marks and a Cert IV.
He did his PPL at Royal Vic Aero Club (RVAC) and I thought they were excellent. Turned out to be a good place for younger people to train, as it was big enough to have good resources, but not so big that a young student gets lost in the rush.
One piece of advice is that doing your PPL part-time while studying full-time will take much longer than you'd think. Start you training early so there is no last minute rush.
After Year 12 he started Aviation studies as Uni and went straight into second year because he already has his PPL, so it turned our very well.