Here's my take:
Your little note about her smile was a great way to start the conversation and show you noticed her. However, you steered wrong by complementing her again as soon as she responded. You should have moved on to the next topic or teased her about something.
Now that she is ignoring you, it most likely means that she is seeing you as too interested and she doesn't feel that much attraction for you. What you want to do is what Crobinson1 says. First don't text her for a significant period of time (also don't go out of your way to interact with her in any way). If you accidentally run into her, be nice and friendly, but generally ignore her (basically don't engage her, other than just enough so it doesn't look like you are ignoring her. Don't flirt with her, and don't try to build rapport, just act mostly uninterested). If she txt's you, respond, but tell her you are kind of busy and you'll talk later and otherwise ignore her unless she gives some really good reason for why she has been ignoring you. If she does, you can re-engage, but do so slowly, and don't compliment her. The best thing you could do is use a push-pull on her, erroring on the side of a neg.
After about a week, send her something like, 'Hey, what's up?'. If you don't get a response, I'd delete her number and move on. If she responds you start building attraction again, but shy away from the pet names and compliments for a little bit.
What you are doing is reframing your relationship. Right now, she thinks of you as the guy who is really in to her, when she isn't that in to you (As I'm reading it). By taking a break, and not talking to her, you will make her question her initial perception of you. Then, when you reengage she won't be so guarded, and as long as you don't trigger any of her Bitch Shield buttons, you can redefine the relationship by this time making sure you build enough attraction with her before you start showing your interest in her in romantic way.
You aren't in the friend zone right now, otherwise she would text you back again.
You want to keep the reengagement light and funny, but start introducing some very vague and non threatening sexual overtones into the conversation through innuendo (this is the safest way to do it so as to prevent her friending you and also build attraction without scaring her).