It is actually possible to use actual/actually too often. 🙂 Consider getting rid of or replacing one or two of those.
In the second sentence (and after), the third-person pronoun refers to an unnamed person identified as “some girl,” so you should use she/her rather than the gender-neutral they/them. (Why, by the way, would only girls — or young women — mistake this character for a superhero? Or even be the only ones to ask? Unless this is what’s happening, or at least how the POV character perceives it, replace some girl with someone, and then you can keep they as the pronoun.)
Because the example eventually mentions more than one superhero, change the hero (which implies this is the only one) to a hero (or a superhero).
Change flys to flies.
I have no idea what the writer meant by or fitness with… superheros (and neither do you), so I got rid of that part instead of trying to find a replacement.
The plural of hero is heroes, not hero’s; do not use an apostrophe to make a plural.
If you want to keep the last sentence from the example more-or-less intact (instead of merging it into the previous sentence), you should change Somehow to For some reason or something similar.
It seems like every day some girl asks you if you’re a superhero. You always sigh and tell her no, but no matter how many times you try to deny it, everyone seems to think you have a secret identity.
One day when you’re walking home, a real superhero flies by and thanks you for helping him hide his true identity. As an additional thank-you, he takes you to his headquarters and shows you around. You try to find a way to explain to him that you aren’t in any superhero league or anything, but you never get the chance.
Now, a bunch of superheroes hang around your house and follow you around, and everyone thinks you know who they really are, so you just decide to roll with it.
(I’m not overly fond of editing writing prompts, but they’re already on the internet for anyone to use, and some of them have lots of errors, which makes them useful as examples of what not to do.)