Great effort! Here are a couple of small corrections: "I haven't exercised at all at university" is actually fine and natural. "I belonged volleyball team" should be "I belonged to the volleyball team." The preposition "to" is needed after "belonged" and "the" is needed before the team name. So the corrected version reads: "I haven't exercised at all at university. In high school, I belonged to the volleyball team and exercised almost every day. I wish I could go back to high school." One small bonus tip: you could also say "I was on the volleyball team" which sounds a little more natural in everyday conversation than "belonged to the volleyball team." Both are correct but native speakers tend to use "on the team" more often.