Why is this 31/f coworker acting so strange with me 30/m.

Not to be rude but it is kind of hard to read the slang. I know my former boss, literally does not like the fact that I might move from his position or ignore him. However the reality is that I am suppose to be under his command. The problem is that many people under somebodies command will often try to avoid working with them. That being said as with him ( my former boss ) you have to let you co-worker that

A. Whatever occurs while we are on the van/bus/vehicle stays on the vehicle.
B. Lunch time you enjoy yourself.

Just get along with them and let them into your personal world, share some secrets or ideas ( not too bad of a secret ) and I am sure they will open up to you.

Like ask via random conversation. Like during lunch or while mobile.

A. What you did before ____( the current position )
B. You ever studied etc, etc, etc.

You have to build up trust and gain confidence. It can be hard not to throw things into your co-workers faces, after learning things, same with families, just learn things that you might connect with them and see how they function,

Usually for me it would start by talking with random co-workers ( as if I was a food-server/waiter/host/hostest ) ask about

A. How do you like ( the work site/ company etc life )
B. Before ( this work ) what you did before this.
C. You study something or have an interest in a subject.

Try to encourage them, and offer them Over-Time if any. I do not know the kind of work you are doing but honestly.....

In my opinion it is the girl co-workers who are more violent, however their are nice dolls their that are open for conversation, but I have to upbeat most of the time and not be cowardly, offensive, or aggressive to anybody. Keep everybody on the same page as much as possible.

If you are above somebody, you have to let them know that you are on their side, but do it without breaking any rules......AKA "If a tree falls and nobody is around does it make a sound?"

.......

You could offer to hang out sometime off the clock and pay for everything.
Like jet-skiing, some event, or maybe go out shopping. IDK but be sure to go for some smoothies or beer or something in an alive or private setting.
Be friendly.....Then you could keep that up, and then move in for your intent.
You get into that friendly innocent kid state ( clean state of mind ).
............

If somebody has kids and you have kid they might not want to play with you.
I know legends of co-workers meeting on the job-site with his and her kids and they got together and became a married couple. Maybe you could do something with her involving the kids if possible. You could be like "bring the kids we make it a family fun thing" and show her your clownish fun father human side.
............
As long as she ( or he ) is under your command they will respond to you as employee to an employer. They have to watch their job no matter how friendly you might appear.

.................She hugged you the first time around maybe you could respond with a hug later on. Point being is that she held back realizing your not on the same pay grade and or level as she is.

A co-worker of mine who was the receptionist was dressing nice with her figure but respectable. Apparently a person in the office probably told her to dress less revealing and literally came to work looking like a grandma the next day. I mean the glasses, mumu, hair up, and would avoid conversation.

You're her superior, there's an uneven power dynamic where she can't be herself.

Leave her alone, she doesn't want to be with you.

She's a subordinate, not a friend.