It's because they're usually teasing and disrespectful, like the "milkmaid" comment I got the other day. And they draw unwanted attention. It makes me feel like a toy.
I have not read all of this thread yet, but it sure has a familair ring to it. I also experienced many problems due to looking very young for my age.
When I got my first regular job I was 21, but almost did not get it because the interviewer had a hard time believing that I was old enough to br legally hired, 16. She requested that I do something to make myself look older when I started working. I decided that wearing a wig might work.
Most of the colors of the wigs that I tried looked very bad on me, one of the colors that was better was a sort of ash blonde. It also had the advantage of making me look even older than my real age, so I got it.
I wore it at work for a while until one of my patients said that she could tell I was wearing a wig, and she thought it would be better if I uncovered my own hair.
The next day I came to work without the wig. Very few people even seemed to notice. I was good at my work and most of my coworkers and patients appreciated that. Most of them treated me with respect, or at least neutrally.
I had the worst time with visitors, who did not know me. One exception was a patient who attempted to grab me in a very rude way. He was old and unsteady, so I just stepped out of his reach and he fell over. Usually I would go to great lengths to prevent a patient from falling. I did not feel bad about that one. I thought he deserved it.
The gist of this is that I do not think it makes a whole lot of difference about how you look. I think what is important is that you satisfy yourself about how you look, and that it gives you self confidence.
I used to joke about comparing makeup to war paint. I said that I wore makeup to give me confidence and frighten the enemy. Lol. I think it could do you good to take the same attitude.
Your comment that the actions of others made you feel like a toy is especially relevant. The bad behavior of others is not friendly teasing, it is a sneaky sort of attack meant to make themselves feel better at your expense. NTs often mask meanness with smiles and by pretending to be joking, especially with vulnerable women.
Not seeming as vulnerable makes you less of a target for such meanness. As someone commented, how you act makes more difference than makeup or hairstyle, although if those adjustments in your appearance give you more confidence, they can help you.
Go to a store with a 3 way mirror and look at your natural stance and adjust it so you seem more confident. Look at yourself walking in window reflections and practice a confident stride until it becomes second nature. Last of all, do what you can to frighten the enemy.
You already know how to make hurtful comments back and are restraining yourself to keep your job. There are expressions that you can let out on your face that show that you could verbally decimate the enemy. One of those looks is worth a thousand words, and is much safer for keeping your job than saying some of those words. People have told me that I really scare them with one of those looks. You can learn to do that too.