My mouse had babies...?

You see my mouse had babies on monday they are four days old now, or at least that is when we discovered them. It's been a long time since ive had babies in the house and and we wanted to get a bigger cage for our two females and her future babies when we opened the cage to get her out we real;Zed she had babies in there. The cage she is in is not the best and i was wondering when would dit be a good time to move her and her babies into the new cage? I am really not sure how old they could be when i looked at them yesterday i could see patterns forming on their skin and can tell they are all going to be brown. There is only four.