Any person who was competent enough a horse owner would know where. I don't even own a horse yet, and I know where to get round pens.
You are going to get judged, no matter where you go. I'm 20 and my experiences are questioned pretty often. Its not that I'm not trust worthy, its that you are taking the life of something living-- and not to mention dangerous-- into your own hands. Any number of things can happen, or go wrong.
What in the world makes you think you need one now? Why not wait in the future when you are older? You are still young, and have time to learn so much. I have my moments where I'm all "rush rush rush! Gotta get ready for a horse!!!" But I look logically and I realize: I'm in NO position right now to own.
Take what you have and explore. A horse is a huge commitment.