No — "a" is lowercase in the middle of a title in nearly every style guide.
"A" is one of the most commonly lowercased words in title case. Every major style guide treats it as a function word that stays lowercase unless it is the first or last word of the title.
When "A" opens a title, it is always capitalized. This applies in every style guide, from AP Style to Chicago Style to APA Style. The first-word rule overrides all other capitalization rules without exception.
Writers sometimes wonder whether the single letter "A" should be treated differently from multi-letter articles. It is not. All major style guides apply the same article rule regardless of the length of the word.
Billboard Style is the only common exception. In entertainment and advertising copy, every word is capitalized, so "A" appears in uppercase even in the middle of a title.
"A" is an indefinite article and one of the shortest words in English, but its capitalization in titles follows the same rule as "the" and "an." Articles carry no independent meaning, so style guides consistently lowercase them in the middle of titles.