Don't mean to cause unnecessary concern! You know your kid best. I think it is actually child dependent as well. As long as the amount of time is not unreasonable and Minecraft is not interfering with other developments, harm is unlikely. I severely limited computer time until DS turned 8 because he would have spent too much time otherwise. He has decent self-control and reasonable judgment now so I can trust him to monitor himself mostly. For him, not having that computer access early on helped nurture a love/habit of constant reading and helped develop a practice of ceative play.
