I think those limits posted in #55 are for EITC.
the definition for qualifying child says “At the end of the filing year, your child was younger than you… younger than 24 and a full-time student.”
My daughter will be 22 at the end of the year, but no longer a full time student. She doesn’t meet a number of the other requirements either (supported herself, moved out in July) so I’m not worried about it, but I don’t think I could take her as she was not a full time student at the end of the year.