Child Support Problem

Hey guys! So I just need opinions on what to do with my situation. All my life I was split joint custody between my mother and father. My father had to pay child support as my mother was the primary provider for me. Well, he didn't always keep up to date as I am now almost 20 and he is back-paying. I never realize it, because it never really mattered, but I never really know where that money is going. My mother is a single parent of 2, has been out of a job and car(uses my car), and depends on child support and government assistance. That will soon end because she has acquired a job. My question is, should I feel some type of way that I am now over 18 and don't see that money? I live with her for the time being because I am transferring schools. That being said, I would love to use that money to put towards application fees, travel for the summer( I have an internship out of state), and to put towards my apartment when I move out in 2 months. I understand that she uses it to pay bills. But I'm about to turn 20 and have never held a dime of child support in my own hand. I know if I bring this up to my mother she will be offended but if I bring it up to my father, he will take it to court. What should I do?