Explore it a bit. Seems like you see her semi-regularly and she is pushing it forward for you. Hard to tell what's going on without more context.
Ignore virginic comments like: "you have to ask her out on the spot!" If I had to stop 15 minutes to set up a date every time this happened, I would never get anything done. At the very least I'd be late for everything.
Enjoy the compliment (if it was one). If it was a compliment, she sees you as high value. If you are high value, she will remain "hot" for you the next time she sees you.
Girls tell me regularly that they are "looking for me" but can't find me because my social media is so sparse they can't stalk me IRL.
This focus on technique, demanding you be hyper vigilant is all silly. If you are high value, you are high value, period. There is a certain line of demarcation which places you in a certain category, apart from others. It's kind of an invisible line, a small circle of privilege. Over time, you will recognize whether you are in it or not.
If you fall all over yourself trying to get a date at the first drop of a hat, you take the risk of disqualifying yourself as a desperate fool. If you see each other semi-regularly, there is a chance to build up a bit of sexual tension, friendly public flirting that can lead to more.
The guys who demand you follow certain strict rules are sexually inexperienced. They haven't developed any social intuition so they have to rely on "rules." Interactions with women are highly variable and unpredictable. I think rules are fine to start out with, but if you use 3, why not 4, or 5 or 10 or 20. It's impossible to keep track of them all. But you can go by feel and experience.
After a while, you'll develop an intuition about these things, and that comes with more experience.
tl, dr: you need to approach more women due to lack of experience.
I´m with
@RickTheToad on this one. Don´t get yourself friendzoned. How is that saying? Strike while the iron is hot or somethin
The reality is, if you are high value, you remain high value. You don't drop to low value status if you don't pounce on a woman the first time she makes a flirty comment. The iron gets hot because I AM hot.