When is it appropriate to go sleeveless to the office? And at what age?

Its 101 degrees here. My office building was built in 1888 and doesn't have great A/C. Thus, I'm constantly hot.

My usual wardrobe has sleeves but lately I've been going sleeveless, wearing dresses and tops (not spaghettie straps, but with about 2 to 3 inches thick straps). Its just too too hot to wear a jacket or cardi.

Now, under any other circumstance I would never ever ever ever do this. I think its inappropriate in a professional setting. So, why do I wear it?

My boss wears sleeveless tops and "dress" shorts. So my thinking is, if she does it, I can too.

I'm never gonna wear shorts at my office, even if they are dressy. We are not some high fashion office, just average. And shorts are not in my comfort zone. But sleeveless is different. I mean I'm 23 with semi-toned/tan arms and I know it won't look bad.

My boss on the other hand is 65. The first time I saw her in a sleeveless shirt and dress shorts I was shocked. Because I didn't realize it was ok office attire

Am I in the minority to think that it is slightly innapropriate for her to be wearing these clothes, to the office? Would you wear sleeveless to the office? Would you were shorts to the office?

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