A bit hesitant as this does seem like unfamiliar territory and I am merely male,....
However, a couple observations and perhaps a point if I may. To me, a crush is an unrequited, one sided infatuation that is not really rooted on who a person is but more on who they're idealized as in the mind of the "crusher". The "crushee" may or may not be oblivious to it but it seems to be more about putting someone on a pedastal as opposed to a mutual expression of interest, or at least involvement. Personally I use the the word "thing" but your mileage may vary.
The general consensus here seems to be that a crush is a bad thing that must be denied and forgotten about as if it were a bad relationship. It isn't even that (at least from what I've gathered) and in reality, nothing bad has been said about the "crushee" here in particular. Why deny an obvious attraction? Do we pick the ones that attract us? Is a power thing? Is it fear of vulnerability? In reality, i have no idea what the crush thing is like for women but I guesstimate I may be close to it if I take my "worst" infatuation and crank it up a few notches. I can think of a few "crushees" that I've known where I was just too scared to risk and I look back and think damn, i'll never know what that could've been. Not a regret per se but rather contemplative reflection. Anyways, my point here is that now, I take the chance and find out. No only lasts a few hours and then it's gone and you feel rather free afterwards. Yes is infinitely more complicated and also possibly just as rewarding. The not knowing is the worst part for me.
That all being said, the real bummer here is that the object of affection is a coworker. Bad news right there, or at least that's been my experience and one I learned from. I wouldn't say don't go for it but just be aware of what the fallout might be. It could be costly and not just emotionally.
The only thing I could offer as advice is to not do anything impulsive, take it day by day and listen to your friends. Lots of advice worth more than I would ever know,....:-)
Just my two cents