Hi, Josephine: you're asking a very important question! If someone from a low income background has an interest in attending college, he or she should be the LAST person not to go for it! I worked in the higher education world for more than 30 years and we were always keen on attracting talent from those who were the first from their families to attend college. I worked at Harvard, Duke, and Williams College and each went to great lengths to recruit students like you . . . and offer very generous financial aid to make it possible to attend. It is critical, however, for you to look for good advice in order to create the best application possible. Many colleges will offer such assistance, as mentioned by the previous advisor. Why not make an appointment over at SMU's admissions office and hear the latest on how to become a good candidate?
Now, if you're really interested in the more central issue of why students from low-income backgrounds don't apply to college, that's a more difficult question to answer. Many colleges attempt to reach out to students in these communities, through college fairs, mailings, and outreach done by local alumni. However, that effort comes up short much of the time. My belief is that the effort has to begin earlier in the educational process, during middle and high school. This requires an effort on the part of public education to encourage and coach all students to pursue education beyond high school. But, if you want to become active in the reform efforts, that's excellent and I encourage you to do so. Contact your local congressman or woman, find nonprofits in Dallas interested in education reform, or, mention this to the folks at SMU and see what they recommend. Not only will you contribute to the improvement of education in the Dallas area, you will also show leadership that will appeal greatly to any college to which you apply. If you Google "education reform in Dallas," I think that would be a good way to start. You'll uncover all sorts of information about many people interested in the same issues you are, and will want to get you involved.
I could go on with more, but I hope you get the picture and have a place to start. You can definitely make a difference in the life of your community and your own as well. Best of luck!!