That nobody - whether they be friends, family, or strangers - is entitled to her sexuality.

That it's priceless - it's not something that can be sold (or held for randsom), no matter the price.

Even in marriage, it's still hers. She can always say no, no matter how pretty the house, how rich the husband.

And just as importantly - though perhaps after puberty has started - that because it's her sexuality, she's also allowed to say yes. Because if she can't say yes, it's not hers.

Also, support her. No matter her choices, or what is forced upon her, support her through everything. Even if it was her choice, and she now regrets it, and it pisses you off to no end, support her.

That's my opinion, and what I do.