Is there a polite way of asking if my friend is Ace?

I've been friends with someone for a year and a half or so, and I wonder if she's Ace. I have little evidence, other than that she wears purple all the time and that she never mentions anything about a sexual/romantic partner nor a want for one. Additionally, she seemed somewhat uncomfortable and didn't have advice when a friend of ours was swiping on Tinder and not knowing whether or not to super-swipe (I don't use dating apps, probably getting terminology wrong or it might be a different app).

The only reason I care if she's Ace is that I am very likely somewhere on the Ace spectra (going with greysexual/demiromantic these days, but ¯\\\_(ツ)\_/¯). Also, if she *is* Ace and maybe is in the closet, it could be nice knowing that at least one of her friends understands (or maybe I'm just projecting how i feel even though I'm not in the closet per se but just want an openly Ace friend).

I'm kinda socially awkward, and don't want to ask her in a way that would make her feel uncomfortable.