Macbook Pro: Why do colors vary on my macbook pro
Yes, that is completely normal. All monitors / displays fade over time and even vary out-of-the-box. All you need to do is color calibrate your monitor. If you are just using this for everyday use then go to system preferences. If you are using this for something like photography or printing then it is valuable to accurately profile your monitor with hardware calibration. 

System Preferences > Displays > Color > Calibrate.