Failed Calculus first year of undergrad, am I screwed?

Is the F I got in undergrad Calculus going to kill my chances of getting into a top-20 program since quant skills are stressed so much? Other than the one F and one W, I was an A/B student. Obviously, I can provide explanations as to what happened but I'm worried I won't even get that chance. I have an undergrad degree in architecture from a state school and a masters in architecture from a Southern Ivy. One thing I'll add is that I was admitted to two Ivies for grad school, but didn't attend for various reasons, but math isn't such a big deal in architecture programs, so maybe that data point doesn't matter. One of my alma maters has a top-20 program, which I plan on applying to.

Since then, I've spent time at non-profits, architecture firms and now in government (all architecture related positions) and have decided to pursue an MBA to open doors in the corporate architecture/development world. I have no desire in going into the financial world and would only consider pursuing consulting if all else failed, two points I'd make clear to Adcoms when appropriate.

For those wondering why the transition from architecture to MBA, it's a long story, but essentially, I've realized my passion and skills lie on the business side of the field and not the design side.

So anyway, what are your thoughts?