Found this on The Princeton Review

It's Junior year and we are basically half way done and next year it's university and college time. It's terrifying for me to think that in about two years we will be done with these class that we don't want to take we get to focus on what we want to do. I haven't yet decided my major because I don't know which on my two passions is what I would like to do. On one side I would like to help people that would like to come here and create a better future for themselves and their kids. But on the contrary side I want to help children overcome their problems because I know how tough life could be. But I have to start thinking about it.

When do I declare a major?

Typically in your sophomore or junior year, but the answer varies across schools and programs. Some colleges ask you to list your expected major on your college application (although "undecided" is usually an option), but don't require you to declare definitively until later.
If you are interested in a major that requires a lot of classes, or classes that are limited to students in that major, then it is better to declare early. Some majors demand a strictly regimented order of courses, and if you fall behind, you may have to extend your college stay by a semester or two.

How to Choose a Major

Consider these factors when picking your major.

• Career Prep

  Choose a major because it will prepare you for a specific career path or advanced study. Maybe you already know that you want to be a nurse, a day trader, a physical therapist, or a web developer. Before you declare, take a class or two in the relevant discipline, check out the syllabus for an advanced seminar, and talk to students in the department of your choice. Make sure you’re ready for the coursework required for the career of your dreams.

• Earning Potential

  Future earning potential is worth considering—college is a big investment, and while college can pay you back in many ways beyond salary, this can be a major factor for students who are paying their own way or taking out loans. According to PayScale.com, the majors that lead to the highest salaries include just about any type of engineering, actuarial mathematics, computer science, physics, statistics, government, and economics. Keep your quality of life in mind, too—that six figure salary may not be worth it if you're not happy at the office.

• Subjects You Love

  Some students choose a major simply because they love the subject matter. If you love what you're studying, you're more likely to fully engage with your classes and college experience, and that can mean better grades and great relationships with others in your field. If your calling is philosophy, don't write it off just because you're not sure about graduate school, or what the job market holds for philosophers. Many liberal arts majors provide students with critical thinking skills and writing abilities that are highly valued by employers.

• Undecided? Explore your interests.

  If you truly have no idea what you want to study, that's okay—many schools don't require students to declare a major until sophomore year. That gives you four semesters to play the field. Make the most of any required general education courses—choose ones that interest you. Talk to professors, advisors, department heads, and other students. Find an internship off campus. Exploring your interests will help you find your best fit major—and maybe even your ideal career.