Shiloh

So I've had this linger in my mind for the past 5 years or so, wanted to see if anyone knows the answer Both of my parents have dark brown hair, dark brown eyes and I have blonde hair, blue eyes, which i guess isn't that uncommon to happen but when my sister was born 7 years after I was, she also had blonde hair, blue/green eyes Is it rare for both my sister and I to have blonde hair, blue/green eyes but our parents have dark brown hair/eyes? Or is this normal?