How could Anna have done that to her own children?

"With tears running down his cheeks, Alexander ushered the girls from the room. Now alone, Anna grabbed the bottle of foxglove. She swallowed the contents of the small bottle and grimaced at the bitter taste. She gasped. The bottle fell from her hand onto the floor. She gripped the sheet as pain suffused her body and her heart ceased." -pg. 20
[image error] How could Anna, a loving and devoted mother, commit suicide instead of allowing her brother to try to heal her of the Smallpox? Anna knew she would ultimately face death and didn't want her daughters to face the same fate. Smallpox was a horrible, contagious disease that killed hundreds of people throughout the 17th and 18th centuries all over North America. As the daughter of a British trader she would have already known what Smallpox was due to the fact by the 18th century, Smallpox had already made its way into major European cities. She may not have recognized the symptoms but she knew what it would mean to be diagnosed with that fateful illness. When someone was diagnosed with Smallpox, it was common practice to isolate them from the public in order for the infectious disease not to spread. Smallpox could spread through inanimate objects, such as Anna wearing her husband's coat after he had contracted the disease. This way is less common. More than likely she caught the Smallpox directly from her dying husband. She had spent a entire night holding him in her arms as he died. Prolonged face to face contact with a person who has contracted Smallpox is the best way for someone to catch the disease. This is why Alexander, when he first saw Anna's rashes, would not be near her. He knew once the rashes had appeared she was highly contagious. Anna had ultimately saved her daughters' lives by neglecting them, sending for her brother to take them to the Shawnee and by killing herself do her children would not come near her body. She knew Alexander would burn her body along with the cabin. Anna had given her life to save her children. 
What would you do if you were in Anna's place?
What do you think the journey was like for the twins after they had watched the cabin burn with their mother's body inside?
How are you liking the book so far?
What do you think of Alexander?