Young Pioneers by Rose Wilder Lane
Newlyweds Molly and David are only sixteen and eighteen years old when they pack up their wagon and head west across the plains in search of a new homestead. At first their new life is full of promise: The wheat is high, the dugout is warm and cozy, and a new baby is born to share in their happiness. Then disaster strikes, and David must go east for the winter to find work. Molly is left alone with the baby - with nothing but her own courage to face the dangers of the harsh prairie winter.