Unless something has changed in the last few years, you need to be under 30 the day you start UPT. If you are just asking the question now, then you'll need to factor in the time to find a unit, interview/rush, complete the application process, graduate from a commissioning source, and PCS to your UPT base. That's probably a good 14-18 months best case.
There is such a thing as an age waiver, but in my 3 & 1/2 years teaching in AETC, I never saw a student come through training who had one.
You're sure age isn't an issue?