I think the simples reason with Sharon not giving straight answers is that, first, she herself does not know much, she has lived a vampire life denying her nature as much as possible so it is unlikely she would go and search for any antediluvian vamp or such. Second, she treats MC as a child, correctly in my opinion. We readers know MC is the real deal, but if you were a random vampire, you would not expect some super OP sexy bitch turn a random guy out of whim and left him to his demise. So when MC, which has behaved as a horny kid, appears with random stuff, she tends to believes is simply that, random stuff. Eventually, she will have to pick up that MC gives her a run for her money.
But yeah, I hope that meeting Mom will answer some questions and advances the plot further.
Too many for confort.