Capitalization for Job Application

Hi, this might be/seem a bit inconsequential, but out of curiosity and in the interest of getting it right for right's sake …

This is more a heading, hence why it's not a complete sentence: "Began as a junior executive and promoted later to District Manager."

My question is should "junior executive" be "Junior Executive?" As I understand it, "District Manager" deserves capitalization because (relative to that district) it was a one-of-a-kind position, so to say, whereas a junior consultant is a standard entry-level pos., of which there were (heck, still are) many, hence my use of the word "a" before it. Almost the difference between a proper noun and an improper one. Am I right in this thinking? Part of my hesitation, and it's a small part, is not wanting to come off as self-important, i.e., look-at-me-big-District-Manager and for them to think I'm capitalizing one and not the other for any other reason than my strict adherence to hopefully pristine grammar.

Please give me your opinion and, if you would be so kind, an explanation with it. Thank you