Although you’ll probably have to pay $160 for the ADX test at a testing center, which is included in your 5-week course tuition here at Sheffield, I would get it out of the way before arriving at school, ONLY IF YOU ARE READY TO TAKE THE TEST a few weeks or more prior to the start of class. Otherwise, take it at Sheffield as 95-100% of typical classes do.
Also, without tutoring, there is a 30-day waiting period before RETAKES.
Please understand, that 5-week course students typically DO NOT take this test before arrival at Sheffield – it is RARE, so don’t worry about it if you cannot do so – you are normal!