Hey there, I can sorta answer your questions for you
Caits has not specified a character limit yet, and she has 2 characters, so at the moment, I'd say that you can have 2, but not sure if you can have more
With regards to the age of the 'children', technically, you can be up to 30 years old, but, 30 years old, would probably mean you would almost be at 50% corrosion no matter what
So, yes, you can have late teens and early adults
But, their corrosion rate will probably be fairly high

I'm sure Caits will welcome you to the group!
So welcome, and make sure to post your characters in the OOC!
Hm... I might be overstepping some boundaries, oh well.