According to the Sept. 1510 marriage date stated in Memorie, Margaret would have been six years old at that time and 16 at the birth of her first son - both of which are possible. I have a bit of a problem with Memorie as the sole source, however, because its historical accuracy is somewhat questionable, albeit it is stated in the preface that "in the more ancient part of the narrative...some pains have been bestowed in correcting the more obvious errors." So, while the text indicates that John married Margaret in September of 1510, it is not sourced by either Somerville or "our genealogists (see footnote)." Moreover, Balfour, in both Vols. 6 and 8 of Scots Peerage only references the contract date, not the marriage date as given in Memorie. Can another source be located that corroborates the marriage as occurring in 1510? If so, I would be happy to add the date to the profile.