You can choose your own pace
There are a lot of ways to study the course. The school I attended allows you to cover the syllabus in a five-day crash-course, but also offers anything up to a six-month curriculum. I have a full-time job, so I signed up for the longest and least-intensive, which took place on the first Sunday of every month from February until July.
I was joined by 13 other would-be wine buffs, just one of whom was in the industry himself; a chef who co-owns a wine-focused restaurant in Stoke Newington. Some worked in finance, some worked in law, all apparently saw the wine trade as a viable escape-route out of office life, hence the education.
While in theory, six months gives you plenty of time to revise, if you have a full time job, you have to be motivated to work under your own steam. Personally, I would’ve gone for a shorter course if I knew just how much I’d have to learn independently.