Usually at that age they don't wean but are distracted, go on nursing strikes, are too busy to actually sit and nurse. Is you lo crawling and exploring or learning new skills? It is not uncommon to refuse breast, especially around 8 months, many babies go through this phase. If you want to continue nursing her, don't get too upset about this, it is not personal. You need to keep it casual, keep offering and when she doesn't want to nurse, pump to keep your supply up. It usually passes within a week or two, sometimes three, that's why it is important to pump not to lose your supply during that time. You can try to offer when she is sleepy or sleeping or darken her room so she is not too distracted with what is going on around the house.
You can also check that website for more info:
http://www.kellymom.com/bf/concerns/baby/back-to-breast.html, scroll down to the bottom of the page for nursing strikes.