rain...parade time

You worry about if it doesn't go well and your dressing becomes and issue, but in essence you are "fishing off the company pier" and even if the dressing is never addressed....you are risking her sabotaging it if the romance doesn't go well. So the risk is mute. If you really like her and plan to have a relationship, then you need to tell. The downside, in my opinion, won't be any worse than if you just have a bad breakup. But you have to take risks to get reward. I'd go for it