My 6 month old spent a day in daycare with a child who started breaking out during that day. Because mine has been down with other things, I am betting there is a good possibility that she is going to come down with it. Due to incubation period, she should start showing signs if infected between 3-23 and 3-30. She would be most contagious as soon as they start.
Let me know if you are interested and I will keep you informed!