She had just turned 15 at the time.
She was 13 when she started writing it, and 15 when she stopped writing in it (when she got captured).
when she was 15 in bergen-belsen camp.
He was 40 years old.
She was 15 years.
August 1944 the family were betrayed to a Gestapo officer, although he cannot remember who it was. No-one knows who betrayed them. :)