How do I know what type of date a date is?
Do you mean MM/DD/YYYY vs DD/MM/YYYY? Or do you mean something along the lines of Birth Date vs Marriage Date?
Sinc you have posted in the Indexing category @Cade Joshua Allred it would help if you gave us the batch number of the project you are indexing.
Sorry I forgot to edit this as I think i know the answer now. I was indexing church records from county Mayo, and they only gave one date, not mentioning if it was birth or baptism date. I guess if there's only one date on a baptism register, it must be baptism date.
Early Irish baptisms rarely included a date of birth, so the date is the baptism date. Children were generally baptized very soon after birth. Infant mortality was extremely high, and no parent wanted an infant to die without having been baptized.