Yeah, I admit I was kinda confused - if the "op" you mean is GRS, I couldn't have legally gone shirtless for about two years before I was post-op. 🙂 I was legally female and had pretty obvious breasts to boot!
If you meant pre-transition, which your clarification sounds like you did... I definitely liked wearing the cutest, shortest jeans shorts I could find in the men's department back when I was still presenting male but planned to transition, and I've *never* been comfortable being shirtless, even when I was a teenager. It felt like people were going to yell at me for being immodest, even though I knew perfectly well nobody batted an eye at a bared male chest.