A colleague and me

Hello LFers,
Hope you`re doing alright.

Here`s a little story for you, I hope you`ll be able to help me out with.
It`s been a very long time since I`ve felt this kind of attraction towards someone, to this degree, and this current feeling I`ve got is slowly killing me.

A few years back I quit my old job and started working, almost immediately, where I work now. I`ve worked in this company for a while now and I`m surprised to say that I have found something I like doing. But it`s not about work, that`s driving me mad.
A few months ago, the company accepted an intern to work. She`s a student, very young (not sure how young, but my guess is 24), very attractive (she`s what one would call a 10) and I really fancy her.
There was nothing of note when we first met. She went through the standard routine of meeting everyone in every department and so I didn`t think anything about it. It was very possible that it could have been the only time I ever get to see her, but that wasn`t the case. She was assigned a job that was very closely knit to what I did at that time (not to brag, I got a raise a short while back). So we ended up seeing eachother every day, at least 2-3 times, we even used to take the same bus to work every day. However when we were on the bus, she`d stay away from me, when we got off - we engaged in smalltalk. As you do.
At work, whenever we had to interact, we`d linger for a minute. I`d check up on her, how she`s doing, she`d check up on me. Really concerned colleagues, right?
Then, something happened and I started noticing her.
She`s very friendly towards everyone and she`s really sociable, so one of my insecurities told me that`s probably nothing - when she lingered at my post and just openly talked about something. But then she began flirting with me, very subtly, but at the same time, when I responded, I felt like she locked up. She would stand close to me, look into my eyes when she spoke and smile a lot. She even broke "the touch barrier". But whenever I responded to her, she would shift and change as if she realized her mistake and corrected it.
I`m not the guy to go after my colleagues, in fact, I`ve always been against relationships at a workplace.
After a while I figured that she`s probably playing games, which I`m not interested in and thus I started turning the cold shoulder. As I do.
Now we don`t get to meet as often anymore, but we do on occasion bump into eachother, just saying hi, hello, how are you. She`s difficult not to notice and I feel like she notices me all the time and for some reason feels like she reacts to everything I do. However, I just can`t put my finger on it and it`s probably nothing. She was just being friendly.

Regardless, she`s left a mark and I`m wondering if this is just me overthinking something that was supposed to be simple or this is me trying to find excuses for it not to be simple, or it really is nothing and I`m just being dumb about it.
I`m not at the point where I`d say I`m infatuated, I simply fancy her, she`s attractive to me and I`d like to get to know her.
How should I approach her and what should I do?

I feel like a teenager at the moment.
Similar to - there`s this girl in my class and I like her, we talked a bit and I guess she doesn`t find me creepy, so is there a chance for something to come of it?

She probably has a boyfriend that's why she was holding back when you flirted back. Anyway, there's something in her mind that holds her back, something why she thinks she shouldn't. Perhaps shes too against romance at work. Find out what it is first, before continuing.

Thank you pcmaster, I did consider that an option and for all I know it could indeed be the case. Wouldn`t be the first time. It all could just be a game.
Then again, how do I find out about that? Obviously asking about it will get me nowhere.

LOL man, asking is the only way. Just ask - Do you have a boyfriend?

She might say yes or she might say no even if she has one. Whatever her reason for saying no, take it as a green light, like she has interest in you. If she is not interested in you and doesn't have a BF she might say that she has BF.

Anyway, you might as well ask her straight out on a date. And then if she has BF she will tell you. So yeah, either way, find this thing out first.

This is all nonsense thoughts?
You want her?
Go get her!
You don’t want her?
Well - don’t then