Thanks, @Spinliesel for this opportunity to use “beg the question”. It’s a first for me.

If there is an antonym for “aggrandize”, it’s not in my Oxford book of synonyms and antonyms. I’ll have to settle for my decades-old memory of having been told by a Roman Catholic nun that starting a sentence with the capitalized first person singular pronoun is prideful and a sin.

Since I enjoy being aggrandized by whoever wants to accomodate me, I will respond to your query only by saying that due to laziness I occasionally type a lower case first person singular pronoun.

I have been under the impression that proper names of things should also be capitalized for sometime now . Cat , Dog , Crow , Table , Northern Boarder of Maine . . . I mean about that , the Northern Boarder is an official place , yet not capitalized ‍
I could just go on . . .

I see claims that the origin of this is that it's a Roman numeral and that it was pronounced as "one" rather than "aye". Whether there's any truth in that, I don't know, but it's a good story.