Not that I know of. But most purebred breeds tend to have a weight range for their type of bodies. For example, the oriental types (oriental sh, siamese, rexes) would be about 5-7 lbs when grown. A persian would be about 9-10. A maine coon would run 12-18 lbs (females smaller) and some of the others like bengals might run mid-upper teens too.
So if you have a cat that falls in a body build similar to certain breeds, you could predict weight.
Most domestic shorthairs have a medium to medium-large body and would probably run 10-14 lbs on the average.
As far as the age thing I've heard (makes more sense) that 1 yr is equal to about 20 in human years and then each year after that you'd multiply by 4 yrs. So a 2 yr old cat would be 24 yrs in human yrs. If you think of a 6-8 month old having kittens - it would be about 15-16 yr old human having a baby.
Our rex Spooky who was 15 when he died would have been 76 in human years.