What makes you jump to the conclusion that she "isn't interested"?
She sounds quite interested actually, in what you don't know yet, but its so much so that I'm sure others have noticed and are just waiting to see how you move.
The best of us don't change up just because we getting some attention. Getting attention from women shouldn't be unusual or odd.
Women are just human beings - they have the same emotions as men do.
If a little attention gets you rattled then you're giving her all the power to do with your emotions as she will.
She should only be just one of the women giving you attention.
All in the car on the way to work anticipating seeing her.
Totally fixated. Goofball ****.
"I know it's a big no-no to ask a co-worker out in a professional setting"
Define "Ask Out".
If you have not clearly defined your objective then how can you ever get anywhere?
Doesn't matter what she wants - at all. Doesn't matter what her interest in you is. That will come out later.
If your objective is to hook up / have sex - then create the environment for that to happen.
If your objective is an actual relationship - then create the environment for that to happen.
Way too early for the "cut off" game because you haven't established anything to "cut off" - you aint even got her number yet Fam
None of this is on her - its on you as a Man, to have a clear objective and follow through with it while accepting nothing less.
Your time is (or should be) valuable to you.
Never let anything mess with your purpose / career / money though - this is a coworker so you'll have a lot going on.
W/O a clear objective you'll end up learning some lessons - especially messing with someone at work.
Nothing wrong with that if you know what you are doing and can mitigate the risks (have your resume ready / start applying for other jobs just in case / save your cash up / etc etc).