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Here is an amazon link to the first volume of My Hero Academia, there are links on it to a couple "How to draw" things too which may be a good option for a 12 year old. Each volume is around 8 dollars. https://www.amazon.com/My-Hero-Academia-Vol-1/dp/1421582694/ref=mp_s_a_1_3?dchild=1&keywords=my+hero+academia+manga&qid=1606394006&sprefix=my+hero+academia&sr=8-3
Try not to get things that arent requested such as some of the other manga recommendations in this thread (Yotsuba is good but a 12 year old requesting Hero Aca probably wouldn't enjoy it).
Amazon has Viz translated volumes 1 - 11 on Amazon with 12 and 13 available for preorder.
https://www.amazon.com/My-Hero-Academia-Vol-1/dp/1421582694/ref=sr_1_5?crid=JB44ZQ2FRCBM&dchild=1&keywords=my+hero+academia+manga&qid=1628960035&sprefix=my+hero+academia+%2Caps%2C175&sr=8-5 vol 1 in stock soon at amazon btw
"What is Fire Watch?"
This is one of my favorite mangas to come out in a long time. It's about super heroes and it has really nice writing. They canceled his previous series which was good but this one is blowing up in popularity. I want this item so the creator can be supported and earn money from his fantastic work. http://www.amazon.com/My-Hero-Academia-Vol-1/dp/1421582694
Funny link: http://45.media.tumblr.com/f67d9f4b9d78a996b99533f2dffe3a6e/tumblr_nzpco9X1ge1sp8ng5o1_400.gif
Boku no hero academia might be up her alley then
Correct me if im wrong but isn't this essentially the same thing? https://www.amazon.co.uk/dp/1421582694/ref=cm_sw_r_awd_NSjMvbWXDBB4D
Look what i found