The Kepler year is about 121 days longer than the Earth year. Every Kepler year is 486 days long. To conform with basic Earth standards, the humans on Kepler (both Mortal and Immortal) use a twelve-month calendar with months named after the twelve months of an Earth year, but Kepler months are always 40 or 41 days long.
Want to convert? Here are the equations you need:
1 Year on Kepler (Ky) = 1 Year on Earth (Ey) + 121 days
Conversion from Kepler Age to Earth Age = Ky*1.3315
Conversion from Earth Age to Kepler Age = Ey/1.3315
Note from the author: Because a Kepler year is longer than an Earth year, the characters in the Mortal Heritance books are actually much older than they seem. For example, Carina is 16 Kepler years old at the beginning of Sisters of the Perilous Heart, which would make her 21 Earth years (16 + 16*(121/365)).
Sisters of the Perilous Heart has been criticized for having a tone that seems too young for young adult literature. This may seem even more pronounced knowing that the characters are actually several years older than they are written as. And here is what I have to say about this:
Terrible things happen in the world, but no matter how old you are, you can trust that you have not yet encountered all the suffering that is possible. There is always something new that can throw your world into a tailspin. The same, however, can also be said about all the joyful, wonderful things in the world. It is never good at any age to be anxious to think like a grim, jaded curmudgeon. Adults who retain the ability to let the world delight and surprise them are a whole hell of a lot happier than those who don’t. They are also arguably much wiser.
The tone of my books will always retain some innocence and youth, but that does not mean they are written for children. Nor does it mean they do not cover difficult topics. They are simply written for anyone of any age with a heart young enough not to have given up on joy. If you don’t fall into that category, don’t read my books.
~Sandy