In a round about way yes, if they are under sized you know they are young, if they are naked you know they are new born. If they are full sized and look fluffy and shiny and alert they are more likely younger adult and if they look dull and frail looking and rather lathargic they are more likely older.
http://www.thefunmouse.com/info/daybydaybabies.cfm That should help
Mice are too small for you to tell their gender when they are only two weeks old. When they get a little older, you can look under their tails for signs. Males will have two distinct openings, with a bit of space between them. Females have what looks more like one long opening, but is actually two openings that are very close together.
Baby mice can be separated once they can see and hear and have fur as long as you can tell the difference between a boy and a girl. Because mice can have babies when they are 4 weeks old!
If you know your rodents, you should be able to tell the gender of baby rodents at birth (I can).
check if they eat solid food. I have 14 baby mice at home (3weeks old), they are quite independent ... I can say your mice will be alright.
by the smell
Mice are slowly weaned by their mother at 3-4 weeks old.
The mice is surrounding the area of food to eat.
If you are looking for information about PET mice, then there is a great website in the related link :)
Well I think its because stars flake and burn out when their really old so that could help them tell.
its called mappy i was looking for it too, i loved that game as a child
Usually by looking at their teeth. It's quite a reliable method.