Shaking Off the Slang with an Online Grammar Checker

I was born and raised in the United States. It can easily be assumed that I speak proper English, right? While I got the pronunciation down, I fail terribly on my writing skills – spelling, grammar, you name it! I am on my first year in college. I have been educated by the public school system all my life. So, all the English I know is slang, so to speak. I am honestly having a hard time writing collegiate papers. It is embarrassing. I actually rely on an online grammar checker to get my writing assignments done. I am completely dependent on it!