Here's a tough one.......at least I think so. Help!

I'm trying to write a formula that will calculate someones age using the following criteria: Your age on your birthday closest to 10/1/2000. For example, if your dob is 4/1/68, your age on your birthday closest to 10/1/2000 would be 33. If your dob is 4/2/68, your age would be 32. Your current age will remain the same or increase by 1 depending on how many days (over or under 182) from 10/1/2000. Can anyone figure this one out? My head hurts.