 The character, Ichigo Morinos given name generally would mean  "strawberry" in Japanese, but in this anime, it is actually "Ichi"  which means "1" and "Go" means "5" which combined together as "15".  The reason for Ichigos given name to be "15" in Japanese is because  when she was 15 years old, Ichigo went in a standstill condition  similar to Kei Kusanagis illness, except it put Ichigo out for 6  years. Since Ichigo is really 21 years old, her physical appearance  is of a 15 year old girl after she came out of the standstill  illness.