I am posing this question for myself, but many people surely are wondering the same, so I think this is valuable for others as well as myself. There are similar questions on the site but they do not ask exactly what I'd like to know. Let me share my own experience to illustrate what I am wondering.
I am currently transitioning to upper division math course work. I have earned all A's in my lower division math classes and some upper division ones at a relatively difficult university, but most times feel as though I just barely pulled off the grade, and only through copious studying. Even when I get near perfect marks, I feel I hardly understand the material. I also tend to forget material quickly. I look at questions from calculus, differential equations, and linear algebra for instance that I only recently learned (math GRE or qualifying exam type questions) and feel I should certainly know the answer seeing as I've taken the course, but can't get to it.
I love mathematics, and spend just about all of my time doing it. The problem is, I see others who are quicker, see deeper, need less examples, and so on, when it comes to understanding the material of any given math class. I want to be a professional mathematician (a professor, researcher, or similar), but I honestly question if I am being naive with this career objective. I wonder if hard work truly can get me where I want to go, or whether I am not cut out for this.
Am I naive thinking I can make a career for myself as an academic mathematician, when there are people years younger who surpass me with their skills and experience? This is a difficult question to pose, because for the last two years my life has been dedicated to mathematics. I would like to dedicate more if not all of my life to math, and go to graduate school for the subject and so forth, but not in vain.
Any honest input would surely help me and likely many others who are in similar situations.
Thank you
I was in a similar situation to yours when I first started falling in love with Mathematics at 18. I had a deep passion for the subject, did well on exams when I put in the time, and spent many days and nights studying and learning intensely. I loved it for its beauty and difficulty, gaining confidence when I could learn and solve difficult problems. As I progressed through my undergraduate studies, I of course noticed others who seem to have a "natural" or gifted ability in it. Merely studying for a day in advanced would earn them just as high and if not higher grades than I when I have put blood and tears to earn my grade.
I would sometimes be frustrated by this, comparing myself to individuals who could party on the weekends study for a day or two and casually get an A on what I thought were tough exams. I shared my feelings to close friends and I learned that you cannot compare others to yourself in that way. Everyone comes from different backgrounds and experiences they have had throughout their lives that led them to be in the same class and take the same exams as you did. Some developed a love and curiosity for math at earlier ages perhaps and have had much longer training in solving problems and thinking about mathematics. Before I had a passion, I liked surfing, snowboarding, arts, chemistry, an array of topics that are not just mathematics. Naturally, some of those who have practiced more are going to tend to be better.
That being said, going to class, studying, and getting A's on exams is not what is going to make you a good mathematician. Of course understanding the foundation is essential, but to become a researcher or professor you must love and enjoy doing research.
During the last semester of my undergraduate I got involved in a research topic with a probability theory professor. The topic involved developing a percolation model to model "pores" (spaces between plates) and develop a probability function that would return a measure of the likelihood plates would slide, causing an earthquake. This was my first research experience and although difficult to do gave me a sense of what it would be like as a graduate student in a PhD program. I was hooked to say the least.
I wanted more, so I searched for more undergrad research opportunities and eventually got involved with UCLA's REU program. There I did research in image processing and microscopy. From there on I really fell in love with doing research and starting studying and researching PhD programs in mathematics.
I also found that studying for the GRE would not be that difficult, with the assumption that doing well in higher math classes I would also do well on these standardized tests no problem. Again, I had the wrong assumption. Taking timed standardized tests are very different then taking exams in college or doing research. They require a different kind of training and also need time and preparation to do well in them. I personally had to take the GRE three times before I felt like I scored high enough to submit my score to various schools I was applying for in graduate school.
To conclude and halt my banter, I did get into a competitive PhD program and still 10 years later I am in love with mathematics, learning, and research. Thus to conclude I would offer this advice; find undergrad research opportunities to gain some experience, start looking into pure math (e.g. real analysis, abstract algebra, etc.) if you haven't already, learn a programming language (Python, C++, etc.), believe in yourself ("I can, I must, I will"), and enjoy the journey. Any journey that is not hard wont be fun anyways :).