If a women 5 feet tall wanted to learn guitar what size guitar would she need?

You don't really need to use a smaller guitar than anyone else. You could get a half sized model or something like that but you really don't have to.

In fact there are a number of famous short guitarists, like Angus Young(ACDC) who is only 5'2 and Randy Rhoads(Ozzy Osbourne) im not sure of his height but Ozzy used to lift him way off the ground with just one arm and Ozzy ain't that big.