I think it is suppose to mean Heisei 17 which is the year 2005. Regardless the story started in 1983 when they were teenagers so at the maximum they both passed in their early 40's.
be me
see chapter title and think that there might be some progress between the two main characters
go into chapter and see the first page
o... o no, its Usagi Drop time
well.... at least the kid is not being neglected so that is something.