I got a B+ in real analysis. Is it over?

Because I do econometrics, some people think I'm naturally good at math. I'm not, unfortunately. I barely passed multivariable calc and got a C+ in my first real analysis class, in the back half of junior year. I took measure theory the following semester, and got an A-, and then finally an A in functional analysis. 

What's important is that you develop "mathematical maturity". You may struggle at first because your brain isn't wired to the way mathematicians think, reason, and exposit. Don't quit. Just move on to the next class. And the next one. And in your despair, against your will, will come mathematical maturity through the awful grace of God. 

I think back to my first proof-based course. I wrote a proof so bad, the TA took it to the professor, who proceeded to write four words: "You are not funny." That made me sad because I was not trying to be funny. So I went into OH (which I don't normally do) to explain what I was trying to show. The professor stroked his chin basically said that my proof was bad, it was wrong, but he said, "this is what research is like." He told me to keep at it. 

Just as a tribute: we knew him mononymously as Alfonso. That was the first and last time I spoke with him. He sadly isn't with us anymore.