
She doesn't have the frame. Even if they put 20lbs on her, they will still have to pad her flat ass. The only thing I can come up with is, they will try to turn her into a female version of Achilles (Brad Pitt), so they may be able to get away with her being slim. From what I have read, she will have a shield.
If they wanted a Jew, Erin Stern would have been a better choice.

Gal can't act either, so I'm guessing Stern would be just as good after a couple of lessons.
The other option is, Kara Zor-El left that space ship as a child and the Amazons recovered her. Kara didn't have to be an adult when she walked out of that ship. I can buy that if Wonder Woman flies. That's a switch in the WW story-line but would work, just a good girl version of Fiora.