Christians Why did God allow this to happen?

My older sister's biggest dream since she was a kid was to become a nurse. She got a scholarship that paid one year in a community college and it payed everything. My sister has a 3.8 GPA and she is involved in lots of things in her college. Anyway for some reason she couldn''t p the ACT and she tried the 6th time. Without ping the ACT she couldn't be in the nursing program FOR FREE . We prayed so hard so she would p it. We have always been close to God since we were little. We fasted and we prayed, prayed, and prayed. This was her last chance and we had faith she would past it. We trusted God and we were sure that he could move mountains. We really needed him to help her p it and my sister studied like crazy. And we don't have money we can't offer the $50,000 she is gonna need and if we got loans imagine how the high interest would be, so basically is impossible for her to finish her college education. We don't understand why God didn't do the miracle we prayed so hard. And now me and my sister are so depressed, all her dreams went down the drain. What we were asking God wasn't anything bad it was for my sister's own good. It was so disappointing because we had lots and lots of faith. So Christians why didn't God allow my sister to p her ACT EXAM if she would've ped it she would've been accepted in the nursing program? and all the hardwork she did in school was in vain since grades don't matter to be in the Nursing Program. So all our prayers were in vain. Why did He allow that? why?