But I'm not a Christian. And I don't expect to change anyone's mind.
Its okay, Christians don't actually read their books in entirety and without excuse making for the lines they don't agree with.
Gabriel offered Mary a chance to refuse "the honor" of carrying Jesus, AFTER she was already pregnant with him (his tone is past tense for her impregnation.) This would imply offering Mary a CHOICE of aborting Jesus.
Coincidentally this particular scenario also offers a great bit of confusion about those who say "well God knew she'd not refuse." This meaning that God never really offered her a choice, because if you know how someone is going to answer, your question isn't a choice.
But like you said, Christians aren't people who read their own book. Especially overzealous types. They're just guys doing what some political figure told them to do, and believing what someone ELSE told them to believe. I've yet to meet a christian who is a scientific evidence based mind, who read the book in its entirety, and stayed a Christian. I'm serious.
Speaking of which, of my three pastors in Wyoming, one's making great money (and you can't get a straight answer from him on anything) one is a poor man who actually shows some awesome "christian behavior" but seems to have some questions, and the last lost his faith and moved away to his prior home. Ironically, the most traveled of the three, who's actually BEEN to historic sites and such, is that third one. Peculiar?