Excluton Expiry

Hi. I am using Excluton for my bc pills and I only take advantage of the free pills in our local Brgy. Health Center as part of their Family Planning program. I just noticed the one that they gave me today has 09/2021 as expiration date. But because it's just month and year, I'm not sure whether it will be expiring on the first of the month or at the end. I asked one of the health center workers and she told me it's still good for one month, but I'm not sure id I'm convinced. Please help me figure this out. Thanks in advance.