First fighting magical girl (and directed to boys) was Cutey Honey, yes. Who the first MG is is a bit of a controversy, since some people claim it's Sally, while others think is Akko (the difference being who was the first animated vs. the first in manga). And of course, everyone lists Princess Knight as the first warrior magical girl, even if she didn't transform, because every manga genre has to track back to Osamu Tezuka.