So then she's making a straw man argument, or you are. Her speech was all sorts of nonsense about how she is so wonderful and also a lesbian, so therefore there is nothing wrong with being a lesbian. IDK what the Mormon doctrine is on temptation and sins and so forth, but in traditional religion, there is also nothing wrong with having sexual feelings or interests or attraction. The sin, the "horrible sinner" issue to which she referred pertains to a category of specific activities, ALL of which are way beyond the pale for 12 year olds. In other words, if she's right, everyone owes Milo Yiannopolis a massive apology and a book deal.

I cannot fully articulate the enormity of your lack of a right to tell people that their 12 year-olds are old enough to hear about sex. It is an individual level of awareness and capacity, that should be determined by people who have the longest and closest degree of acquaintance with said children and presumed to have their best interests at heart. In other words, their parents. If parents think their kids are old enough to hear a talk about why lesbians are awesome, that's their right. No one else has the right to subject their children to such a talk however, absent the parent's prior approval. As I said in the original post, no one brought their kid to that event expecting to have them exposed to that, and the speaker and her idiot parents had no right to impose it on them.
Insert the word "your" into the appropriate place, and the statement is fine. Without it, absolutely not.
Not necessarily a good thing.
Experience with that practice inspired people to start raising the ages of consent and marriage in the civilized world. Ditto. And generally in cases where responsible people judged them capable. It was usually NOT the rule of thumb of kids of that age, or even substantially older, to be so accorded such privileges. Even the marriages, for example, were contracted on their behalf by parents, and their own opinions on the matter largely superfluous.
Not at all. And I know lots of people who were confirmed at 7, BTW. It does not entitle you to anything. It does not change your status or your rights or privileges. An unconfirmed adult is still of superior status and dignity to a confirmed child. Confirmation or the age of reason are entirely internal states of being, between you and God. "Age of reason" merely means the age at which someone can be held responsible for their own sins, and thus need to confess them, and inversely, the age at which it is possible to appreciate and respect the Eucharist.