True Fire by Gary Meehan

This starts off with a girl sixteen years old, pregnant. Sneaking out of her house where she lives with her grandfather and twin sister Gwyneth. Parents long dead. Her name is Megan and her plan is to meet the father of her baby Wade, who ran off when she told him she was with child. (JERK.) She met Wade because her sister was with hid brother (Holt) and coerced her into being with him. While she's with him near the corn fields basically arguing they hear loud cries (must be fighting at a tavern) Alas no It is the whole village screaming. Wade makes her hide and goes to see what's happening (although I'm pretty certain he hide her on purpose because he knew something and was scared for her) A man in black armour cuts his head clean off with an axe. *ARGH WTF*