When I sat down to plan SMatPA I wanted to make it as canon-compatible as possible – down to whatever detail I could wrench out of the canon sources. However, one notable stretch is the Scamanders. I knew that Luna got married quite a bit later than her friends from Hogwarts – Harry & co. – but I always imagined her twin sons to be in the same year as James. How? Why? Well, maybe it is easier to understand if you look at the marriage customs I’ve grown up with.
My own parents didn’t get married until I was one year old. My aunt and uncle still aren’t married but have two teenage sons. I’ve always had the impression that marriage is something that makes paperwork easier, and it’s a legit reason for party without having a birthday, but getting married is completely optional. Luna has always struck me as a rather comfortable person who would live her life as she seemed fit rather than how customs tell her to live.
As it plays out in my mind, she and Rolf decided to wait with the wedding because first it was too stressful to arrange a marriage during a pregnancy (Rolf’s excuse) and once the twins were born they could just as well wait until the boys were old enough to enjoy it (Luna’s excuse). Thus I put their marriage to approximately somewhere around the time the twins were six year old or so.
For those curious, I also have thought of their wedding clothes.
Luna’s dress would be a very pale yellow (remember Bill and Fleur’s wedding when Luna and her dad came in bright yellow?) accented with blue flowers in her hair and bouquet. Rolf would wear very dark blue robes with yellow details, thus making them both a mix of Hufflepuff and Rawenclaw.