What are the requirements and prerequisites of becoming a Scout Sniper in the USMC?

I'm Enlisting in October and I'll be on DEP for about 4 months. What MOS should I take or do I need to take to qualify for Scout Sniper.Also how long will I need to be in the service before I can apply for Scout Sniper?Also any other information on how to get to that point or how LONG it will take me to get there please let me know as much as possible.I'm not just some kid thats interested with guns and fighting by the way.I don't have the money for college but and no one really believes in me and I want to prove to everyone that I can do something with my life and I want to earn the respect of the people I know and people I will meet.