Though it's not really difficult to build a pc from scratch for yourself, doing so the first time might be somewhat tricky and so i'd ask a friend who has done that to come over and help you build it together

maybe there are some shops where you can order one with your choice of pieces but they assemble it for some fee, which is imo a good compromise between premaids, where you usually buy things you don't need/don't know what's really in and doing it completely for yourself.