Hi, Cait!
I'm not
entirely sure what you're asking so I don't know whether my answer's what you're looking for, but I'll give it a go anyway...
From the
Time Warp Information thread:
The 'warp' itself was really more of a 'slide' - it pushed everything in Wizarding history back 38 years, for example, the publication of a (wizarding) book in 1968 became a book published in 1930. Someone born in 1960's birth certificate read 1922 instead.
So you just calculate their birth year as you normally would, regardless of the time warp. If Cait's uncle is 34 (I'm assuming
this is his app?), I think he'll either have been born in 1916 or 1917, depending on his birth date. I use
this age calculator to figure out ages, so maybe that'll help?
(Let me know if this doesn't actually answer your question, though.)