that maybe can adapt to this situation -- her thing is that you can show your cleavage or you can show your legs, but if you're showing both, you've tipped into trashy territory. (which is your right. But if you want to avoid it, I've found she's very much correct that one is fine and both turns you into a Bundy, to use a very dated reference.)
Anyway, as a person with a pretty stylish octogenarian mother, she's not sparkly from head to toe -- but one sparkly item absolutely looks great on someone who is no longer in their traditional sparkle era. I even think it can look pretty chic.
In general I agree with you -- wear what makes you happy -- but if you feel self-conscious, just do one. It tends to work well.