Mar 14, 2019
Roy is 6-7 years older than Sin!
That's how I came to the conclusion, that Roy is older than Sin:
Since there is an official birthdate for Roy, we know, that he is born on the 13th July 1991, which means he should be 21-22 is season 2 since Oliver came back from Lian Yu in the year 2012.
How I found out Sin's possible age is way more complicated. We know, that the picture of Sin, which her father kept in his wallet and then gave to Sara, was taken on the 10th May 2008. We also know, that her father crashed on Lian Yu one year later, which happens to be 2009. He also told Sara that Sin was 12 years old at this point. That means that Sin had to be born in 1997. So in Season 2 Sin was 15-16 years old.