Helping Family Historian users since 2002
https://fhug.org.uk/forum/
I think the actual legal ages were 12 for a girl and 14 for a boy and this seems to be backed up by this website:Marriage certificates, which were also organized in columns, give the following information: the date of the event; names of the bride and groom; ages of the bride and groom (the record may only indicate 'of full age,' which usually meant over 21, but occasionally signified 'over the age permissible': 14 for girls and 16 for boys until 1929); each spouse's 'condition' (bachelor, spinster, widow, etc.); each person's rank or profession; the bride and groom's respective residences at the time of the marriage; fathers' names; and fathers' ranks or professions. There is also an indication of the form of the ceremony and the signatures (or marks) of the couple, two witnesses, and the officiating minister or registrar.
I think that just because the certificate says of 'full age' doesn't necessarily mean that they were.The marriage certificate probably offers the best boost to research of any document. Not only does it tell you the exact date of the marriage and the full names of the couple, it also includes their ages (however, it might just say 'full,' meaning of age; around 75% of marriages certificates just list 'full' until the early 1850s. If it says 'minor' or 'under age' that means between the ages of 12 and 20 for a girl and 14-20 for a boy, at least until 1929, when the lower age limit for marriage became 16).