I'm absolutely new in this forum but I got a bit of experience with the shy-type, so maybe you ll find my input helpful.
Expect the shy type to be flaky at the start, its her natural anti-slut shield.
Shy-high-value girls want power in relationships (they use passive-aggressive tactics) you have to be prepared.
(They are used to be in full control and having guys all over them)
That response she send you is a struggle for power over you, remain your status, DONT play into it.
(Probably valid, still she doesnt give a shit about you losing money and planning stuff for you to do, until she compensates for that in whatever manner! Its just nice stuff shes used to get trown at her from all the boys)
My advice:
Dont text her too soon, next week she said, gosh you got better things to do at the moment (what about the other hot chicks pursuing you at the moment?

so delay it as far as your comfortable without screwing the timeframe. (Its all about the push and pull)
For the message itself, rely on the experienced brothers I d rather not touch your game due to my own inexperience.
Dont be like the others bro, be alpha! :3