Gender: girl
I agree with the researcher that the two, Mira and Maria, could NOT have been the same person. Firstly, even if she "lied about her age" how could someone so much older be registered in school with other children in Lodz? Secondly, the Maria who was born in 1910 was registered in the Hasag Pelcery labor camp in the Czestochowa area, while the Mira who was born in 1924 was registered in the Lodz ghetto list. The 1910 Maria survived the war, if I'm not mistaken. I believe this discussion was a bit of a red herring, and that they are clearly two different people. That's my two cents' worth!
Also, I forgot to add earlier, if you look at the Ghetto Fighters museum website and see the photo archives, there are several photos of Mira (aka affectionately as Mirka) Kaluszyner with other girls from a youth movement in the ghetto in 1941 -- there is no way an older woman would be in such a youth movement.
If I understand correctly from the earlier reviewer's comments, the reviewer was not saying that Mira lied about her age to make herself seem younger, but rather to make herself seem older. If we take as a given that she was born in 1924, it is perfectly reasonable that she would have been in school in Lodz (Gymnasium) in 1941 at age 17, as well as in a youth group. After deportation to Czestochowa, there is a possibility that she might have been faced with a situation where it would have been advantageous for her to say that she was 34, rather than 20, years old--or she might have fudged her age only a few years, to 1920, and the other number is a typo. Without further evidence either way, we cannot say absolutely for sure these are not the same person--but I completely understand your skepticism.