Yes it's okay to eat Greek Yogurt everyday if you want too and you can eat as much Greek Yogurt as you want too without any issues.
Greek Yogurt as well as other yogurts contain a lot of calcium, protein and probiotics that are essential for good health and an improved immune system.
Eating Greek Yogurt or any other yogurt everyday can help boost your immune system and can help make you feel better sooner when you have the flu or cold virus.
Eating yogurt including Greek Yogurt may even prevent you from getting the flu or cold virus as well as many other diseases.
It's recommended to eat yogurt everyday so you won't do your body any harm eating yogurt everyday if you want too.