Can you correct my grammar ?

"Many things have changed after my High School graduation. This past year has been like a rollar coaster. I prefer to keep myself and my life very active. I'm constantly doing something in life. School is not necessarily my most favorite place to be, but I continue to go there to get a good education. I enjoy to skimboard, occasionally surf, work in my garage, read good books, and hang out with my girlfriend and do silly things with my friends."