none of the characters look their respected ages in any way

Just stop
the anime age debate is always stupid because the design isn't ment to be realistic

Do you not know that humans come in all shapes and sizes?

@Mr_Sai its not just about looks, the way they act is way older too, i have no problem with lucky star because atleast they kinda act their age

Then it's realistic. At the time people were considered adults around the age of 12. So the age of 8 at that time is the same as the age of 12 at our time when adulthood is the age of 18.

irrelevant
peter griffin acts like a torddler most of the times even tho hes a grown ass adult
what do you want tokiyuki to shout gen Z crap and watch skibidi toilet all Day?

@ejleon no 8 year old looks remotely like that lol

@Rukasumi so you lack any experience with different sized kids, just say that

Some documents from the time describe tokiyuki's age as 4 years old.
His age varies from document to document.

That's not what fallacy is. Fallacy is a logical error in an argument. So no, this is, in fact, not a fallacy. And actually this is true.
Secondly, kids act as kids today because they don't have responsibilities. At that time an 8 year old, like you've seen in EP1, was trained to be a soldier, because at the age of 12 they could go to war.
Thirdly, the fallacy is when you talk about acting as 18. No one talked about being 18. You shifted the goalpost, because otherwise you couldn't refute me. You said that he acts as 12 in your eyes. Yes, in today's standards that would be 12, when the adulthood starts as 18 ( 12 is 2/3 of 18), but at that time adulthood started as age of 12, that's why kids had to "mature" faster, and that's why he acts as an 8 year old.
Lastly, he is still pretty childish. He doesn't really understand that he could die. The battlefield is just a playground for him and that's why he thinks of it as a game which was also highlighted in the show several times.

You literally didn't say anything that is remotely a plot hole or/and refute any of my statements.
GJ

Re-read my comment and try again.

I cannot for the life of me fathom anybody over the age of 15 seriously caring about the difference between an 8yo and a 12yo. A kid is a kid is a kid. I can barely tell the difference irl much less in anime, appearance and behaviour wise.
Like, unless you're a kid yourself or a parent/teacher of kids in that age group suffering from a terminal case of deformation professionnelle, I really can't see why this is something you'd get hung up on when the story would change in no meaningful way if they looked younger or were actually 14yo.

lol, what is happening lmao.

irs anime bro...they aren't real people. and anyway, I in real life, sometimes people dont look their age. I don't see what would get you so annoyed..
do u get annoyed when you watch Hollywood teen dramas where the teens are played by 30 year Olds??