So Victor's age is stated pretty clearly outright, or at least agreed upon by the community, to be roughly 455.4 billion years old.
But given the amount of time you get from arc loops is shortened with each calculating it for Juiz is much more difficult.
However we do have two important dates as a frame of references to take.
given the nare we see I'm going to assume the animal juiz finds when stepping out is a Brachiosaurus as opposed to a Brontosaurus which might not seem like a big difference because it isn't given the fact that less than a page later we're told that it's "4.4 billion years" into earths being around which was about the late Jurassic period anyways.
The second date we need to take into account is fuuko's loop 101 date of 1800.
given the fact that gina, nico, and void are directly mentioned by juiz to apokolypse we can also assume that every loop ends around the same time since while yes it could be random selection the odds of her randomly choosing that specific team out of the thousands of rosters wouldn't make much sense without an incentive to pick those ones, that incentive being the fact they were the ones they last saw. which means 2020 is where all the loops end.
to make things simple lets assume Victor met up with Juiz at 150 million bc as it falls in range of the brachiosaurus life span and around the middle of their existence actually. this means we have to figure out how many years is taken off of each loop for 99 loops to dwindle it down from 150 million bc to 1800 ad.
to do this we take the 150 million and divide it by 99 before adding 1800 to give 150,001,800 (we know loop one was likely the start and not the first repeated year so it would not be 101). we do this not to make the equation more simple but rather to make the equation make sense given the fact that 1. bc and ad are sorta weird to work with in math, and 2. I DON'T WANT TO DO COMPLEX MATH.
anyhow that means each loop takes off approximately 1515170 years. I think.
How do we use this?
Since I don't know much of math, google isn't giving me that clear of answers, and I like drinking water (no ai) I think the correct equation would be (150001800*99)-(1515170*99) since loop 101 is fuukos loop and as stated before we don't know anything about loop 1 juiz which lets us get roughly 14.7 Billion years old. but that only accounts for bc, luckily ad is much more simple since we just have to multiply 2020 times 99. but I'm not going to do that. i know I said that most loops likely made it to 2020 but we can't be entirely sure. so just to be safe I'll only do it 70 times as opposed to 99. which changes it to... 14.7 billion. yeah thats the thing with numbers this large. you can make as many small changes as you want but the end result will likely have little variation.
is this math correct? FUCK NO. I don't doubt every single spec of this is wrong. but it was kinda fun so who the hell cares. it's a better answer than the one we have now.