I'm completely clueless on the process, but on track to graduate in two years, so I have a few questions about what I should do.
1) What's the difference between a Master's degree in Mathematics and a Ph.D in Mathematics? I have always wanted to teach mathematics at the college level, and so my family has always joked that I'd be in school forever to get a Ph.D. What is the difference between the two, and how do I go about choosing which is right for me? I don't really know the difference between undergraduate and graduate school, except that the latter is supposed to be much more difficult, much deeper, and is the starting point for research for many people.
2) What do I need to go to graduate school? At the moment, I have a 3.6 GPA, which I guess is alright, but I don't know if it's good enough or if there's anything else I need. I have awful test anxiety, and so my GPA in mathematics specifically is probably a lot worse than my overall GPA boosted by my minor and general electives. I am working on getting an undergraduate research opportunity to help put weight behind those numbers. Is this an appropriate things to do in undergraduate, and is it going to help me go further?
3) I have to come to realize just how expansive mathematics is through my time on MSE. There are tons and tons of fields of mathematics with all kinds of interesting problems. At the moment I'm really fascinated with differential equations because that's what Stony Brook researches at the graduate level, so their undergraduate course is like an introduction. If I decide I want to do that, how can I find other schools with similar focuses? If not, how can I figure out what I do want to study? It seems I'll never experience even the surface of some of these fields that are particularly deep.
Sorry for the long post, but thanks for any insight any of you can offer.
I can only give you a definitve answer to 1), 2) and 3) seem to be dependent on the country/university/college/etc. that you are visiting. Since I'm from Europe, I cannot give you complete answers for 2) and 3)...
Now to the answers:
1) You will receive a master's degree when you successfully complete graduate school. For this, you usually study for about 1.5 - 2 years (after you finished undergraduate school...) and write a master thesis, as well as do the final master exams. To get a Ph.D., you need to have visited and completed graduate school, then find a research group which will fund your Ph.D. thesis. This thesis is an autonomous research project, which usually takes about 3 to 4 years to finish. At the end, your thesis will be evaluated and you need to pass an exam about your project (or rather, the subject of your project). Granted you pass, you will receive a Ph.D., which is roughly speaking, the first "real" academic title you can get. Afterwards, you can change into the private sector, where you will generally assume some leading position in research or administration, or you stay at the academy and continue towards your professorship.
[tl;dr]: M.Sc. $<$ Ph.D. (regarding ability, know-how, experience and future job possibilities)
2) Here I cannot really give you an answer, since I do not study in the USA. But clearly you will need to complete undergraduate school. Which qualifications you will nedd to attend graduate school in mathematics, I cannot tell... Yet doing some research projects on the undergraduate level can never be wrong, as long as you still have enough time to complete what you need to complete. It is especially useful for gaining insight into your prospective field or method of research, which might reveal that something else would suit you better, or that you are exactly where you need to be.
3) Basically, as with your other questions, you should do a consultation on your future career. I'm sure your undergraduate school will have some sort of advisory service. They will most certainly know exactly what you'll need and where you ought to go. Last but not least: Take your time choosing your field of study! It can be a quite painful quest, and you should still be able to change fields of study/research later on (as long as they are at least somewhat connected, so with math you would have a good starting point to get into physics, chemistry, biology, even things like psychology, medicine, etc.)
I hope that clears out some of your questions. Also, you might want to consider editing your question, since you may not give enough information (your school for a start...) to get satisfying answers.
Anyway, I hope I could help!
Sincerely, SDV