If the bride or groom was "underage" - under 21 - at marriage they were supposed to have the permission of parent or guardian, although that person was rarely named (unless as a witness). Some couples appear to have got around this requirement by marrying in a different parish.

It was only the 1841 census where ages were rounded, although some people gave increasingly younger ages as they got older. Some also changed their ages if much younger or older than their spouse, especially with a second marriage.

It is usually difficult or impossible to find a birth date before the start of civil registration - only the baptism - unless it is given on a MI, or unless they emigrated to a country which gives this in a census or on a death cert. Or unless they recorded the date in a bible, in letters, or in other documents.

Sue