Well, thought I’d post a link to ‘Part 2’ which was an entry into the same Workshop as Marknew’s ‘The Super One’ (theme = "Someone gets superpowers and this makes someone else upset")
http://www.superwomenmania.com/storybank/bank/’Z’upergirlz%20-%20Film%20at%20Eleven%20by%20Lfan.txt
Not much, if any, ‘growth’, either size or muscle-wise, but definitely involves the "girl gaining strength" theme if that is your cup ‘o joe!
Please forgive the atrocious typos and lack of proofreading.
Peace
LF
Great start to this story! I think I see where this is headed, and with the hints dropped by Marknew’s post I’d like to offer a humble suggestion. If Superman did lose his powers I think it would be ironically funny if, while trying to make restitution, Z "accidentally" only makes him into a backwards spelling magician, that the other members of the JL underestimate 😆