<human>: Can you summarize the given text in a few sentences?

So I [31 m] have a crush on a lady at work (she works in a completely different department and area of the company) and we've been slowly building a rapport since last year. Earlier this week I asked her if she'd like to grab lunch sometime, and she said yes, and was totally cool with when I told her it would be on me. We're set for this coming week, and I'm both excited and nervous. I mean, I take it as a good sign that she said yes to lunch with me, but that doesn't automatically mean she's into me. What do you guys think? If the lunch goes well, should I ask her out to dinner? What are the signs I should be looking for if she's into me? Every time we chat we have a pleasant conversation, and a good flow. I've been out of the dating scene for a while and my ability to pick up on non-verbal cues is lacking.
<bot>: I like a girl at work, asked her to lunch, she said yes and want to know what to look for if she shows interest in me too.