The former 'Dance Moms' star published a lengthy video Saturday, which pretty much hit the point home that she had, in fact, come out after much speculation these past few days. She says she's gotten tons of support, and has never been happier in her life to be her true self.

At one point, one of JoJo's fans asks how she identifies in terms of sexual orientation ... and she says she doesn't know yet. That's interesting to note, because everyone assumed she'd come out as gay ... mostly due to her own wardrobe, which literally had the word printed on.

JoJo showed off a shirt she received the other day, which reads ... BEST. GAY. COUSIN. EVER. Many took that as signaling, not to mention her lip-syncing to Gaga's "Born This Way."

It's a big deal, BTW. JoJo -- who's 17 years old -- has a massive audience with kids, so this is gonna reach them in some shape or form. Many think it'll help children be more comfortable with owning their sexuality, since one of their on-screen heroes now has.