It is absolutely possible to make a 55 minute connection from N to C gates if your plane arrives on time, you're near the front of the plane, and hustle.
It is absolutely a ton of additional stress to make a 55 minute connection from N to C gates with more than one child, one of which is a 6 year old, and likely not sitting near the front of the plane. If *anything* goes south, e.g. a slight delay on arrival, you will be stressed to hell for the start of your vacation.
Neil