[AbiDrew85]

As a genetic male, forget sizes. Don't bother. Just don't.

Get a professional fitting from a trained expert. I recommend Victoria's Secret, Kapreeza, or Jolie Femme. All three are staffed primarily by women, but they are also trained in professionalism and candor. It's awkward the first time but they will quickly make you feel comfortable because they care more about you as a customer than you as a man in women's clothing.

This is actually largely true of cis women as well. Sizing varies wildly between mfg's, brands, styles, etc. A youtuber I'm following recently demonstrated that she had bras with band "sizes" from 32 to 36, and all actually measured exactly the same with a tape measure.