quick and easy answer. It looks to be a Japanese clone of a Singer 15. Lots of info here about them, but the numbers mean very little and age is a crap shoot.
That said. I am puzzled by the harp space. It looks like it maybe be a 3/4 sized 15. Not many around. It also has a quick release for the presserfoot. Kinda neat if you vary your workload a lot. I would have been quite happy to find it.