Is It a good Idea to ask out a female co worker?

Okay, so I have been working at this office for over a year now. A girl was hired probably 6-8 months ago, in the company, my company founded (so we do not work directly together, but in the same building). She will stop by my desk and chat almost everyday at work, she's gone to happy hour with our group several times, and last week, her, myself and one other co worker went golfing after work, and then went out for some drinks after. She gave me her # a while ago for HH arrangments, and we will even text to one another occasionaly. I ask her different questions to learn more about her (thing is everything I learn makes me like her that much more), and definitly have shown that I have an interest. And it seems to me like she may as well. How can I get a moment alone to aks her to a movie or dinner or something? Is it okay to just call since she gave me her # already? I'm nervous to ask her because I have not admired someone like this before, any suggestions?