How much time you let your kid play video games is always up to your judgment. Just don't go overboard with the restrictions or they won't want to do anything else once they have the freedom to play when they want.
It is good that you are implementing some limits on the time your kid is playing video games and gadgets. Kids nowadays are very inactive and are not engaging in physical activity enough, that is why most of them are overweight and unhealthy. They are also missing out the great view and nature of the outside and playing sports and friends with childhood friends on the street, just like the old times. I have a ten year old cousin and his parents are also limiting the amount of time he spends on gadgets. He gets upset but my aunt is still strict about it. She lets him do sports like volleyball and swimming and also enrolls him in some music, voice and painting classes, just to keep my cousin away from always immersing himself in video games and gadgets.
