I'd trust her instincts, she's usually right, however thats not to say that the tortoise hasn't grown more and male charactoristics haven't become more obvious since. We really need pics to be able to tell.
One of my females (and she is definitely a female) has a little 'claw' at the end of her stubby tail. When figuring out what sex your tortoise is, it's more about the shape of the tail (fat and short on a female, long on a male) and the shape of the vent/cloaca (looks like an asterisk (*) close to the body in a female, looks like a slit at the tip of the tail in a male).