Yep. The expiration date is the last day it can be used.
So, if my first use was April 3rd, would my exp date be April 2nd 2019?
If you purchase or activate an AP on 3 April 2018 the expiration date is 3 April 2019.
Approximately true, but...
If you merely PURCHASE an AP, the date is irrelevant (except for making advance FP+ reservations, which can be done using only a purchased, but unactivated AP certificate.)
It's only the date that you ACTIVATE that AP that matters concerning the useful life of the AP.
An AP can only be activated in-person at WDW.
(And, yes, you CAN purchase and activate the AP on the same date, if you are physically at WDW to do so.)
Yes I was using "purchase" to mean an in-person purchase and use of the AP, as opposed to the purchase of a certificate (which is why I said purchase or activate). If I go to a ticket window and ask to purchase an AP they are not going to assume I mean a certificate to activate later (you would have to specify that).
NOW, a guest can purchase an AP and/or "activate" the AP at WDW ticket window (or Guest Relations) and that AP
will NOT actually be fully "activated" (the year won't start "counting down") unless and until that guest takes the AP
to a park and enters the gates using it. (That may be a day or so later.)
A subtle (but, in many cases, significant) change.
That's interesting, so what is the date on that AP then?
Or did they stop putting dates on them?
Can I still use my AP to enter a park on the day it expires?