I think it is always important to rule out a physical reason for a change in attention. Is she getting enough sleep? Maybe she isn't seeing the board clearly? Has she had recent ear infections or a cold that could have blocked her hearing? Often children don't understand subtle changes and "act out" because they can't explain what's wrong. As a parent the first thing I would do is take her to the doctor to rule out any physical changes that could be effecting her school performance.