>>105365884Because when the character was made she was introduced as a young teenage girl. When Superman was introduced in the 30's he was already a grown man, not to mention the Silver Age stories have him being a hero called "Superboy" when he was a teenager.
Also I am pretty sure before Supergirl was introduced there are stories of Lois getting powers and going around and calling herself Superwoman.
Also calling gorwn women "girls" isn't seen as something bad, it's why we have a show called "Golden Girls" with old women and no one but radfems care. It's like how men, including older men, will call each other a lad and a lad is pretty much a boy.
