Agreed with everyone above. 27 1/2 used to be the age at which you had to be in pilot training, but that was close to 10 years ago. It has been 30 for some time (I turned 30 in UPT). I know many units will use 27 as the cutoff age that they will offer interviews because it can take up to 2 years to process the paperwork, gain approvals and get the clearance investigation completed (although it's not required to enter UPT). This allows for a little slop if there are any waivers, medical or otherwise, that need to be worked.

Don't settle on one unit either. Interview with everyone you can, get in if possible, then down the line, transfer to wherever you like.