(skipping over the what is a year/how is time judged on different planet thing)
When there's that sort of thing I always assume that birth-toddler years are similar to ours then either they continue to age as we do until puberty or at a slightly slower rate but then once they hit 20s time begins to slow. So aging their equivalent for 10-15 =/= 20-25, but then once they hit closer to middle aged it really slows down so each year after 35 might be like 10 of our years but then after 40 it's 20 of our years and at 45 it's 30 years per year, etc.....
no subject
When there's that sort of thing I always assume that birth-toddler years are similar to ours then either they continue to age as we do until puberty or at a slightly slower rate but then once they hit 20s time begins to slow. So aging their equivalent for 10-15 =/= 20-25, but then once they hit closer to middle aged it really slows down so each year after 35 might be like 10 of our years but then after 40 it's 20 of our years and at 45 it's 30 years per year, etc.....