In first chap, his age is 23. Then in later chaps, gal is 23 as well. In 1 flashback, dad is 23 and daughter is 8. The difference is 15. He adopted her at 15yr when she was 1. So. if we add 15yrs more to the daughters age to get the current age. We'll also add 15 yrs to dad's age. That gives the daughter's age to be 23 and father's age to be 38. And the mc's age to be 23 as well. So when daughter was 6, he was 21.