Maybe we should change the 28 years after bit, cause if this is 9 years after the 19 years after epilogue, I'm getting these ages for characters:
James Sirius Potter - between 21 and 24
Albus Severus "Al" Potter - 20 to 21
Lily Luna Potter - 18 to 19
My calculator does not lie! >.>
Edit: whoops, that would make Lily 18 to 19, not 19 to 20!