I displayed lots of behaviours for years that I was obviously trans (debating with my male friends that being a girl is way better than a guy, being happy whenever a friend would say I have the personality of a "cute girl") but I never once questioned my gender identity.
I would argue this only validates their claim - there was already a level on which you were arguing for and practicing feminity, but hadn't connected that to a personal desire and ability to be a girl. You had a conscious awareness of all the aspects, you just hadn't packaged them together in an understanding of the whole.