I'd need a bit more details with your story to be certain.
It is typical of girls to expect boys to do all the work, usually at the beginning. (I know it's unfair, but we're afraid we'll get labelled "easy" or "silly" or something. =/ We're also more passive when it comes to flirting and even if we like someone a lot, we'll wait for him to make the first move ... or at least be very obvious.)
So when you say it "cooled down", that might not mean anything. Flaky? What does that mean lol ?
The fact she got in contact with you again is a great sign. It means she's ready to DO something to keep in touch.
Your question is tough to answer.
To a lot of girls, it can be both at the same time, or the former (only looking for attention) can evolve into the latter.
Give some updates and I'll give my opinion. Right now, it could be both, but look for signs of her possibly flirting (such as staring at you during pauses, trying to get the conversation going constantly, perhaps making you jealous, laughing at every joke, acting happy in general, twiddling with her hair, being a bit nervous, trying to touch you in some way ... etc.)
As for now, think more about what YOU want. Be confident and don't look into it too much. If you like her loads, you could directly ask her out if you've known each other for long enough. That way, you'll get a hint at least. :)