She may have no idea you like her in "that way", I was always completely clueless that a guy liked me even when people told me it was obvious! (low self esteem is a wonderful thing!)
I wonder if she is still at that dating bastards age where you don't want a nice guy you go out with goodlooking jerks who treat you badly. You would be appreciated by an older woman (than 23 not necessarily than you) who realises that nice guys are the way to go and you deserve to be with someone who treats you right.
I think you need to let her know how you feel but away from work and in a way that won't make it awkward if she isn't interested. Perhaps having you treat her well will make her realise what a jerk the boyfriend is but don't count on it, some of us don't realise until after the wedding!
You have nothing to lose here except to feel bad in the short term, will it matter in 10 years time if she rejects you? NO. So go for it. And post all the details
I love living vicariously!!!