It would be best for you to ask her out now.
Do not keep engaging in small talk with her.
She has known you long enough that this is no longer necessary.
Just ask her out.
If she is playing games with you, she will either not accept your offer or give some kind of excuse.
This is how you will know for certain where you stand with this girl.
The next time the both of you talk, you should ask her out.
No more banter.