@zmx1716 see the above post for the answers to your questions! @BAbound hit it on the head!
As far as a 4.0, it is definitely NOT easier to get a 4.0 in college for the very fact that you have free time! That makes it so much harder because you constantly have to decide for yourself when you will study and eat and socialize, etc. and sometimes your homework gets lost in the mix. I only made a 4.0 last semester because I honestly did not socialize that much. However, its all possible! You just have to learn how to balance your time. The content is not hard, its the time management that gets you.