I've been out of the system for a fair while now, but I note it says here
General Requirements | Aviation Corps Officer (SSO Pilot) - Defence Jobs Australia you have to be between 17 and 49 years of age on entry, so age shouldn't be too much of an issue.
The RAAF says maximum age 43 with a preference of maximum 27.5 - not sure why they've gone the half-year there!
Anyway, do a bit of research and give it a crack. Good luck!