Telling gender with a difficult chinchilla...

I was attempting to bond my chinchillas and a thought crossed my mind... What if Lilly isn't a girl? I had previously adopted my oldest girl believing I was receiving a male. When I took "him" in to be shown how to properly check hair rings well... there was nothing to check for hair rings. I adopted Lilly from someone who said she was a she and that's what the breeder had told her.

I've attempted to try to check but she's such a squirmy little girl I can never get a good look.

I'm trying to spare a vet visit because she's is so skittish. Is there anything I would've seen by now if she was a young adolescent male?

Sorry if this all sounds stupid, it's probably just my paranoia kicking in :wacko:.