AITA for telling a parent what i wear is not their decision?

So I’m a choir director for a public middle school (grades 6–8) in South Carolina, and I wear this jumpsuit for concerts because I think I look good in it. Also, I’m a 28-year-old female. So this is me at a concert wearing it. I think it looks good. I don’t enjoy wearing dresses as much after I got this. https://media.kohlsimg.com/is/image/kohls/7570131\_ALT5?wid=800&hei=800&op\_sharpen=1 This is it on its own. I never wear it without a shrug to school events because I know a lot of skin would show. I had this parent, a dad who has two kids in my class, and for all their concerts I pretty much wore that. We have three concerts a year. Last year, the dad said that I needed to switch it up, and then at the winter one he told me that it was ugly. I let it slide, but the next time he said I was attention-seeking. He also told me it’s not feminine enough and that I need to be more ladylike. I literally was stunned. His wife was also there, but she wasn’t there when he had said it. His ex-wife is also very sweet. He has come up to me four separate times. I genuinely think I look good in this, and it’s one of my favorite things I own. I used to wear black dresses, but they didn’t really feel like me. Also, lots of moms and female staff have complimented it. Also, our dress code for choir concerts is concert black—you can literally wear whatever you want. This goes for all the kids. So then, at the last concert two days ago, he said he would get me fired for wearing this, and I said, “What I wear is not your decision.” Also, the principal, the first time she saw me in the jumpsuit, loved it and even asked for the link to where I got it and said I looked amazing. This sounds fake, but girls, you know there are men like this. I’m literally covering all my skin, so I really don’t know what’s wrong with what I’m wearing. And does it look bad on me? So I need to know, AITA? And girls, please tell me if I need to wear something else or if this is “not feminine enough.” Also, at a concert last year—the second one for the year—I had worn a black dress instead of the jumpsuit. He told me that’s what I should be wearing, not the other thing. After that, I just stopped wearing dresses and kept wearing my jumpsuit. My last post got taken down, but please, I need to know.