Depends.
On a lot of things, like what strain of mice you have, what fat% and protein% you feed them, the number of babies in the litter, etc.
If you take a couple of day old babies to feed to hatchlings, the rest of the litter will grow faster, and if you have a momma that doesn't care for her litter and you add to another momma's workload, those babies will grow more slowly.
Also, you'll occasionally have a litter that grows slowly and never reaches adult size, 'dwarf' mice, I like to keep a few of these around for XXS babies for new hatchlings. If you don't selectively breed these out, or keep them isolated, you'll find you mice will grow very slowly and eventually all your mice will be runts.
I had a few mice around that were comical in appearance, the males had abnormally large genitals but they were otherwise stunted. They took about twice as long to reach small adult size, and never got any bigger, but they were otherwise healthy. They were always the dominant males in their domain, and would kill each other if allowed to mature together. They all had a certain 'look' that was obvious once their coat colors came in. They were all good breeders, but occasionally they popped out a litter of runts. Once a few of these pop out, you got some dwarf blood in there somewhere, and if you wanted them to mature more quickly, I'd assume you'd want to start over with a different strain. I dunno, might be from excessive inbreeding. I raise mostly rats now, just keep a few mice around for a source of live pinks for reluctant feeder hatchlings.
