So you got your answer. She can't now.
That means "no."
1) I'm unsure exactly what she feels. She's said that this is something she may/does want to explore at some point, but I'm not really sure what that means, and she takes weeks to get back to questions on the topic.
If someone said that to me? I would tell them
"To me that means you may want to explore it at some point but not any time right now or maybe not with me. So... it sounds like a soft NO. So I am going to take it as "no" and let the romance go and keep it as friends. If things change, you can let me know. We'll see what we see then. Is that the ballpark we're at here?"
To get the verify right then.
Because I think I'm hearing a soft no. I think you notice it too with feeling like "a kid with a babysitter crush" and feeling like she "tolerates you."
Disappointing, since you like her so much, that she's not as into you.
But you could take it as a "nope, not happening at this time" and choose to move on rather than choosing endless suffering. You could choose to "un-suffer." You could choose to end it firmly with one last verify on it so that you know for sure, and so that YOUR health and well being can move out of this zone you don't seem to enjoy and into the Healing Space. Maybe something like...
"So... I've tried to get responses a few times and I don't want to be a pest. You seem lukewarm. I'm going to take it as a "No, no romance at this time. Keep it as friends. Am I right?"
Take bull by horns and get your final answer and then let it go if it is indeed a "No."