I'm re-writing a question I posted yesterday, put in a way as general as possible which may hopefully be of use to others in the future in a similar position.
I would like to pursue a career as an applied mathematician. I'm interested in mathematical modelling of real world systems in areas such as biology and physics. And I'm generally interested in using deep mathematics to solve problems.
I want to keep my options as wide as possible, and want to make sure my mathematical training allows for this.
I'm currently studying for my Bachelor's degree in CS and Physics. After my Bachelor's I will pursue a Master's in applied mathematics. I'm debating whether to switch to a Math major for my Bachelor's, to get more rigorous math training.
My question (which I think is generalizable to many people), is about the kind of mathematical training one should attain to succeed in applied math, and keeping one's future options wide.
Is highly-rigorous mathematical training important for this field? Is one mathematically limited in their abilities, if their major is a non-math-STEM-field (such as CS and Physics)?
Or is the level of rigor in a typical non-Math-STEM-major serious enough for wide horizons in applied mathematics, and leaves room to fill in the gaps during the Master's?
If I might, let me focus my area of concern a bit:
I'm able to take a few extra math classes in my current non-math STEM Bachelor's as needed. I can also always fill in a few specific courses in the future, before my Master's. So I'm not that concerned with missing 2-3 math topics in the Bachelor's.
My specific question is along the lines of: Is the high-rigor sustained throughout a math Bachelor valuable for the aspiring applied mathematician?
Do I end up limited mathematically, if I "skip" this level of mathematical depth and hardship, and stick with mostly the CS/Physics/Engineering level of math understanding for most of my Bachelor's?
I just came across a post on this site which talked about Mathematical Maturity. This is exactly what I fear I might be missing if I don't go the Math-major route:
... fearlessness in the face of symbols: the ability to read and understand notation, to introduce clear and useful notation when appropriate (and not otherwise!), and a general facility of expression in the terse—but crisp and exact—language that mathematicians use to communicate ideas. [...] And also: The capacity to handle increasingly abstract ideas.