Japanese girls calling each other Kanojo

I've heard a girl calling her close friend "Kanojo" 「____ はもうずっと私の彼女」, （i remove the girl's name）full context is, she was asked which person she wants to date, she answered "____ はもうずっと私の彼女". In the U.S it is normal for two girl best friends to call each other Girlfriends, is it the same in Japan? Or is it different?

Is it normal for two girl best friends in Japan to call/refer each other as "watashi no kanojo" or My girlfriend?

No, in Japanese "kanojo" isn't used to show platonic friendship in the way "girlfriend" can be in English. So if Girl A refers to Girl B as "watashi no kanojo," the implication is that it's a romantic relationship.

That said, Girl A could be saying it jokingly, especially if she's exaggerating some sort of possessive feeling about Girl B for comedic effect. But in any case, if a woman is simply talking about a platonic relationship female, she usually wouldn't say "watashi no kanojo."

So in other words she’s Lesbian without admitting it?

Hi,

she was asked which person she wants to date

Are you saying that she was asked if she wants to date person A or person B, and then she chose a girl named C? If so, my guess is that she could not or did not want to choose between A and B, so she chose a third person C who just happened to be there.

Or if you're saying that she was asked to choose between A and C, then there is no surprise there.

「So in other words she’s Lesbian...?」

Maybe, but not necessarily. Like I said above, it could be something she said jokingly. Imagine, for example, Yoko is a single woman who's not dating anyone and owns a cat named Tama. When someone asks what she's doing for Valentine's Day, she says "I have a romantic dinner planned with Tama, since he's my boyfriend."

That probably wouldn't mean that Yoko is into bestiality, but rather that she's exaggerating the bond she has with her cat as a joke. It's pretty much how I might say, "There's nothing in the fridge to eat, but as long as I have beer, I'll survive." Obviously I can't survive on just beer, but I really like beer, so I'm joking about that being all I need.