Nice to see a tidy Kastle.. You can find some info about the company, and the frame designers, etc, on this site, (just use custom search, rh top of the page) but there are no catalogues. I have a Degree 3.5 from '94-5, suspect yours is later. Decals are different style, yours looks later. Also, no Degree 5 is listed for '95 in my July '94 MBUK, but there's a Deg 4 (Alivio) and 6 (LX). You can look at your Shimano codes, on the brake arms, chainset, etc. I think yours will be T- or U-, for '95 or 6. Second letter of code is A for Jan, etc.
This isn't the actual age of the bike, of course- but is a "not earlier than.." sort of guide..
Enjoy your Kastle, I think they're a well-made brand, great geometry too- my 3.5 is a reliable favourite..
Regards, Steve.