"How old are the ladies?" is not accepted. The suggested solution is "How old are the kids?"
When a Spanish noun has an -ito/ita ending, the English word "little" precedes that Spanish noun's translation. Thus, if you only goal was to communicate, then the translation you propose should be accepted. However, be aware that translating "señoritas" as "young ladies" is preferable, more literal. and hence better.
All the more reason for you to report it. When enough people do, it will be accepted by the program.
See. Here you translates "las señoritas" as "young ladies" which I used for translation for "Las señoritas tienen vestidos bonitos" and you wanted "young women". Very inconsistent.
I guess senorita is "miss" and senora is "mrs." (not yet married and already married respectively)
Años means years, and is a masculine noun (always), so you would want "Cuántos años". Anas means a genus of ducks.