I've been playing guitar (and several other instruments) for many years. I would say it would be easier for your child to start with an electric guitar because the strings are easier to depress and let's face it they're going to eventually wind up with an electric guitar anyway so why not start with one?
A nice entry level Fender Stratocaster or Telecaster would be good. Then pick up a good multieffects processor (Boss makes a couple of nice ones) and maybe a small Fender practice amp to go along with it. That should last your child quite a while without growing out of it.