After you have attained the rank of Life Scout, you must be an active member of your unit in that rank for at least six months to qualify to work towards an Eagle Scout project. You must also serve in a position of leadership during this period. There are 21 merit badges total that you need to earn to be considered for the Eagle Scout award, including all 13 on the following list:
First Aid
Citizenship in the Community
Citizenship in the Nation
Citizenship in the World
Communication
Cooking
Personal Fitness
Emergency Preparedness or Lifesaving
Environmental Science or Sustainability
Personal Management
Swimming or Hiking or Cycling
Camping
Family Life
These requirements can be completed at the same time as the Eagle Scout service project. There is no need to do all of them before you start your project!