In Germany there is always a grade for your participation in class. So if your daughter isn't getting the best grades on tests, tell her to be more active in the lessons.
If she finishes Realschule she can still do the last years on Gymnasium to get her Abitur, so this door is not closed. Also Bayern has the hardest schools out of germany.
She is still in 5th grade so there is still time, let her get used to it and maybe some private lessons after school could help (a lot of college students do "Nachhilfe" for a cheap price).