Is there anything wrong with online gaming?

My mom sets specific times to play (about 3 hours a day). It sounds okay, but in the actual game you can't progress on your characters at all. She believes spending so much time on the computer is unhealthy, but I don't think so. It's not like I'm neglecting my work. I still do all my summer school assignments and I'm receiving better grades than most of my friends. I don't do as many activities as them, but I'd rather just do what I have fun with. I'm also a bit shy and socially awkward, but I can maintain a conversation. I also do volunteer work during the weekends.