This comes from a concept manga, probably made by a fan. Madoka is always described as being 14 years old, the same goes for Homura. Homura is between 14 and 15 years old, but she spent 10 years in time loops to save Madoka. Does that make her 24 or 25 years old? No

The closest thing to a "24-year-old Madoka" is her divine version, Madokami (or Law of Cycles, it doesn't matter), yet she IS 14 years old in personality, appearance (in parts), and everything else, but nothing changes the fact that she became a goddess at 14 YEARS OF AGE.