Welcome!
Tail length at that age and how quickly a bird feathers out are usually highly unreliable indicators of gender and often are entirely random. I've had fast feathering birds and very slow feathering birds, birds with long tails at that age and birds with short tails at that age. All were pullets. And I think all your birds are pullets as well. As I understand it, it's typical for white leghorn pullets to have long tails for their age (this is also true of easter eggers) so some of your girls having long tails is totally normal