So, let me see if I got this straight. You and this gal looked at each other but did not speak for how long? A month? A year?
But you did not speak and did not introduce yourselves.
And now, seemingly out of the blue, you call her by name and then you text her.
She is thinking - How does he know my name? How does he know my texting info? He was just some guy I smiled at, at work!
If I were her, I'd be freaked out, and I bet she is, too. There is a high likelihood that she is blocking you from any future messaging. From her perspective, you are a relative stranger who she never gave personal information to, but who somehow has it. And that can mean that you feel like a stalker to her.
Moral of the story - don't skip over vital steps! And the MOST
vital step was either one of you going up to the other one, sticking your hand out and saying, "Hi, I'm ____. I noticed you are always so cheerful every morning. I bet you know where to get the really good coffee around here."
Since you were interested in the contact, and she was not initiating it, and it was important to you, it was up to YOU to initiate it.
Instead, now, I bet it feels creepy to her. That "not introducing due to awkwardness" has now turned into "never talking because you've creeped her out."