Approver Comments:
Thanks for taking on the often tricky task of finding the identity of someone who didn't sign a first name, just a first initial. I agree with you that Miriam Znamirowski is the most likely candidate in the database for being "M. Znamirowska." Her age, as you noted, is also within the likely range for a Gymnasium student; in 1941, Miriam would have been 13 or 14 years old.
One of the reasons for the last name disparity is that, in Polish, last names often take different forms depending on the person's gender. Last names that end in "ski" or "cki," for instance, will often be changed to "ska" or "cka" for a woman. The record from which her entry in the database was developed might have been entered incorrectly, or the official taking the record might not have known about the naming convention. Maria might have signed the album "Znamirowska," but someone else taking down her information might have entered the male or gender-neutral "Znamirowski."
Something else that is curious is that Maria is listed as a "Schneiderin," a tailor, rather than a student. This might reflect a later occupation in the ghetto, after the closure of the schools, but most students are listed as "Student" or "Schueler." What do you think?
I'm going to mark your research as "confirmed," since I think we've found M. Znamirowska. Looking forward to seeing what you find in the next stages!