There were 3 names that were exact matches for Chana Cedrowska, but there was only one born in the right age range for her school and to have signed the album.
According to Chana's record, she was deported (along with the rest of her presumed relatives) on March 30th, 1942. According to the Secondary Source list, there were daily deportations to Chelmno during March 1942, and this is where I have concluded that Chana went.
Searching the rest of the database for Cedrowska, I found other people with the same last name that lived, at some point, at Hamburgerstrasse 40, 18. These include Sura Cedrowska (b. 1894, possible mother or aunt), Rejzel Cedrowska (also Rejzel Kuperman, b. 1887, another possible mother or aunt), Szewa Cedrowska (b. 1924, could be an older sister or cousin), Estera Rachela Cedrowska (b. 1916, could be a much older sister or a cousin), and Jocheweta Cedrowska (b. 1877, possible aunt or grandmother).