But you should feel better. There's something big to consider you should take comfort in. The Holy Spirit leads the true believer into truth. If that young lady is deceived in any way, yet she is born of the Spirit, she will learn the truth.
We have all spent our lives learning to understand sound doctrine, learning some things in scripture say something different than what we may have initially thought. We weren't damned, for not understanding all doctrine, and none of us understand everything, to date. But we can take comfort that the power of God, the Holy Spirit, leads into truth, it sure that basic seed of the gospel, falling on the good ground of the repentant heart before God, will grow into a tree. Nobody plucks anything from God's hand.
As a mature Christian, are you fooled by any of it? Well, I'm not either. You can also count-in a number of other dittos to this, from other users here, under the BDF bigtop. Don't get exercised that you need to, as if, hide false doctrine from peoples' eyes, refute every crackpot statement. What's important is people get saved, first, then the rest will follow. Anybody who is a deceiver is wasting their time, only deceiving themselves and those who they can deceive, which are those who don't yet believe, as, and this is important, true believers are not forever deceived. See what I mean? If that young lady believes, offer what you can, but take heart she's in God's powerful hands, not people of their private, crackpot religions, cults, tares or message board trolls.
You give some people of the world too much power, to think they're damning anybody by telling lies. The world is full of lies, everywhere you look, but it's not causing you a problem seeing the truth, is it? Well, we can thank the Spirit of Christ, Christ who overcomes the world, Christ who gives us eyes that see and ears that hear! Have joy in this, offer what you can, and leave some spiritual things for God to sort out, because He will.