This good girl has been a crush of mine all through high school. She's a church girl. sweetest, kindest and most gentle person i've met. and the thing that gets you is that she's a flirt. but when it gets time to the next step she gets difficult. My friends tell me maybe its because shes just reeeally nice and the times im thinking shes showing me interest its really only because shes nice. Now i would normally believe that but theres two things that stand in the way. One is that in high school i know for a fact she was interested in me and i blew it back then. and second is that now till this day she send me texts like this:

"I spent time with eddy today, made me miss you!" (eddy is a close friend of mine)

She doesnt say," hi ","hey","whats up", nothing just straight out sends me something like this. we don't see each other ever and if we don't make an effort too we most likely never will so i always try to invite her places or say to have a quick coffee to catch up. She aaaalllways says "yes" and then when the day comes she ends up saying she cant. What the fuck!
Lately i've stop showing her interest and stopped inviting her places but i do try to escalate things when i talk to her. when i give an ioi in a convo she responds back and flirts. BUT i also know i lower my value giving these ioi's first. so im not sure what to do.

I've already showed much interest and told her i miss her a bunch of times, etc. she responds positively but i dont know if shes nice or really interested. I've stopped starting conversations with her and now i always wait for her (once every 2 weeks) texts and try to escalate and then just end up failing because she stops answering the texts. I never ask her why because i feel it would be too needy to ask. How do I switch this around even more and make her attracted to me as she once was in high school.??????????????????? Or how do i test her to see if she is interested already?