Believe me, I understand that paranoia. It will serve you well when you are in college or at work. But if you have a deadline that's a ways away, it's good management to look at it now, but let it percolate in your head for a little while before you get started writing. Like, you've figured out what you want to do for the second project, but you haven't started it yet. The idea will probably mature for a few days, and you'll be able to put something better together for spending some time thinking about it. As long as you have enough time that you can afford to wait those few days and still get everything done, you might as well take it.
