How did 9/11 shape your military career?

Depends on the field of the work. For example, for militarism it is crucial to have a college degree and develop the relevant skills and values (you can read here https://writingbros.com/essay-examples/military-and-professional-bearing-why-army-values-are-important/ more info on this matter). Thus, I think you should firstly check the career requirements, read more details and choose the major if required.

As a Marine Science Technician in the Coast Guard, my entire career revolved around safety - doing OSHA-type inspections on ships and the facilities they visited, and pollution response. It was a good living and I enjoyed the hell out of it.

I was selected by my Rating Force Manager (head of my entire career field/MOS/AFSC) to be part of a "Rating Review Panel" to plot out what kinds of stuff my fellow MSTs would be doing for the next four years. We finished our intro and broke for coffee - and saw 9/11 unfold on live news.

We reconvened and after we had all called our units to see if we needed to go home, we resumed our work by reviewing our job description in the HQ descriptions of what we were supposed to do. At the VERY bottom was a note about "... and port security functions as needed" and we ran with it. We spent the week reinventing our career field and took the lead in qualifications and mission essentials for the entire Coast Guard. I went from doing 90% safety and pollution (with 10% paperwork), to about 60% security, 30% safety and pollution (and that damned 10% paperwork). Everything changed... and it was a blast!!

USAF 1961-1965 Active, +2 yes. Inactive Reserve... If I had been young enough, and passed a physical, I would have joined again!!!