She wasn't a very big or major character except for being Luke's guardian. She did risk her life for Luke and that did show she was courageous and ready to sacrifice her life.

Loving and brave woman, she HAD to know that someday Vader and the Emperor would come looking for Luke. She had to know the dangers of that, and yet she still stayed and raised Luke on the moisture farm on Tatooine. It's a hard scene to watch when Luke goes back to the farm to find her and Uncle Owen both incinerated beyond recognition.