Approver Comments:
I agree that Hendla (watch how you spell her name in the comments) is the most likely candidate to have signed the album as "H. Pankowska"--as you suggest, in 1941 she would have been 16 years old, an appropriate age to be attending Gymnasium. You'll also find her last name spelled "Pankowski" in the database, so you'll want to input that spelling on this stage and follow records for "Hendla Pankowski" throughout your research. (-ska was a common ending used for females, while -ski was used for males, but a German taking records might not necessarily have followed this convention--or it might have been mistyped over the years.)
Also note her addresses: Holzstrasse 9 #36 and Zieten 20.
Nice work, see you in stage 2!
