Arthur Ransome Wiki
by Bill Wright. Since this is quoted text it should be edited for style not substance, unless you are Bill.

During the action of Swallows and Amazons (SA), Bridget Walker (then called Vicky) turns 2 years old. At the beginning of Swallowdale (SD), which takes place the following summer, she is said to be already 3 years old, but this is before her birthday, which occurs just after SD is over.

Could this aging by 2 years in the course of one calendar year be a remnant of the discrepancy between the dates of the two books? Using this as a theory, she turned 2 in 1929 (the original year for SA) and 3 in 1930 (when SA appears to have actually taken place). Thus she would turn 4 on her birthday right after SD is over.

Considering the shift this character goes through--a name change only lightly explained--if Vicky is a nickname, why would her birthday cake in SA have "Victoria" written upon it?--and that she would be more convincing a character as a 5 year old in Secret Water than as a 4 year old, I'm willing to assume she starts SD as a 3 year old, and that the "2 year old birthday" is a leftover of an earlier, incompatible, chronology.

This page uses content from Guide to Swallows and Amazons series by kind permission of Bill Wright.