One definition of an acronym is:
An abbreviation formed by (usually initial) letters taken from a word or series of words, that is itself pronounced as a word, such as RAM, radar, or scuba; sometimes contrasted with initialism.
An initialism is:
A term formed from the initial letter or letters of several words or parts of words, but which is itself pronounced letter by letter.
If I pronounce an initialism, as a word, and not just as letters, does that 'make' it an acronym?
If you look at the third definition of acronym, it directly addresses your question. BBC is an acronym, regardless of whether it is pronounced as letters or as a word. RAM (random access memory) is an acronym whether it is pronounced ram or are-aye-em.
SUPPLEMENT
There is a controversy as to whether initialisms are a subset of acronyms or a distinct class of terms.
Several dictionaries seem to restrict acronyms to those shortened forms that can be pronounced as a word. See, e.g., Oxford Online, Collins, and American Heritage.
Others include initialisms as a form of acronym. See, e.g., the OED, Merriam-Webster and Websters New World. Wikipedia has an article on acrnoyms which notes a difference of opinion as to whether initialisms should be included, and then proceeds within the article to include them. It also notes that there are a number of forms that do not neatly fit into either category, such as JPEG (pronounced jay-peg) and AAA (usually pronounced Triple A).
There is also the interesting evolution of an acronym found in the abbreviation for Standard Oil. It began with SO, a clear initialism, which them morphed to ESSO, a classic acronym. (The company has since become EXXON which does not seem to stand for anthing.
NATO is pronounced as a word "nay-toe" and not as "N-A-T-O" similarly BBC is pronounced "B-B-C" not "bbbck" or something similar.