I got multiple asks about the way angels age ♥ Info-dump ahoyyyy!
Aging is Weird in angels! There is a difference in growth-rate between bonded fledgelings and unbonded fledgelings.
Unbonded fledgelings grow at a steady, moderate pace, with stages that can be sort-of compared to humans.
Bonded fledgelings age dependent on what their bondmate ‘needs’. This makes that no bonded angel ages exactly the same! As illustrated: When Dean gets Cas, Cas is itty-bitty and cute and completely helpless. The first few months, Cas gradually warms up to Dean, and their bond starts forming tentatively. After about a year Cas is so attuned to Dean and the bond that his angel-instincts pick up on the fact that - unconsciously! - Dean would feel better if he was less fragile. Because let’s be real, how many times would Dean have a frikkin’ heart attack every time he rolled over in bed and almost crushed the fledgeling napping there, huh.
So a transformation of sorts starts. This is actually really unpleasant for the fledgeling because you get a lot of growth crammed into a freakishly short period! Their entire skeletal structure has to grow, which is of course painful. As well as their wings- all feathers will have to be replaced with bigger ones as well, and it itches like Hell when they fall out and later grow back in. Fledgelings usually get really lethargic and quite ill from the entire process :(
Cas stays toddler-sized quite a while. Dean is (again, unconsciously! keep in mind, Dean has no idea he has anything to do with it) completely content with him staying at a perfect size to get coddled and picked up and snuggled and so on.
In contrast, Cas stays ‘older kid-shaped’ far shorter. By that time Dean is mostly just eager for him to grow up because he’s realized the world isn’t fun for angels at all, and he would feel far, FAR better if Cas at least was physically able to defend himself (broken record but: unconsciously~)
When Cas is older teen-shaped (last pic) Dean learns of the bond, and massive spoilers ensue :}
ALSO: these are only four stages that Cas has had! He’s had a lot more, mostly because Dean was, well, expecting him to hit specific growth-marks, I guess?
But yeah, some fledgelings have practically no ‘childhood’. If they’re unlucky enough they’ll end up with a bondmate that wants them adult as soon as possible and they spend the entire time till adulthood in a state of accelerated growth, with all inconveniences and horribleness that comes from it U_U (…I think you guys had already realized this AU can be wickedly heartbreaking but still I’m sorry)