Bananas are very healthy for you so yes it's OK to eat a banana everyday if you want too.
I eat at least one banana everyday along with my breakfast and when I'm eating cereal I like to slice up a banana and add the sliced bananas to my bowl of cereal.
The bananas contain Vitamins, Nutrients and Minerals that we need to stay healthy and they also contain Potassium which is very good for health.
Eating bananas also give you energy through the day and are a healthy snack.
You can eat as many bananas as you want too each day and you'll still stay healthy although if you eat more than a few bananas everyday you might get diarrhea or have to poop more often.
But it's okay to eat bananas everyday if you want too.