This is a question for women that are 21+?

It started last summer when I started noticing this girl from my high-rise. And over the year I started noticing her more. Then one day I decided to talk to her, while both of us were on the elevator. The first conversation we had was about our iPhone ‘haha’, which was something pretty random. Nonetheless, as time went on, after a few more encounters of "Hi, good morning, and have a good nights". I finally asked her what her name was. Of course this should have been the first thing I should have done, but because I'm not use to these things. That was not the first thing that crossed my mind. So after finally discovering her name, I waited for our next encounter to gather all the manhood I have and asked her out for a beverage sometime. Her answer was “yea sure, but I gotta go, I will talk to you later?” Now, the reason why she sounded rushed, to my belief was that she was in a hurry to catch the public transit. And once again not being use to these things, I forgot to ask for her number or give her mine, so we can REALLY have that chance to talk later. So, I guess my question for the women reading this is; was she interested from the answer she provided? But I mean if she was why add “gotta go, I will talk to you later” without any actual exchange of a way to get a hold of one another. And what should I do the next time we meet again? Do I make the move once more and ask for the number? Or should I see what she has to say about going out for that beverage, to really know if she’s interested?