As GS said there really is no pressure. My first course was the Hadrian's Wall one and I was a bit concerned as it was the first online course I'd ever done and I was worried about having to get things done by deadlines etc and people chasing you up. It isn't a bit like that though, you work at your own pace and if you don't want to do something, you don't do it! Even if you decide it isn't for you and drop out, no one asks why.
In some of the courses I've done there have been quizzes to help you and at the end of some of the weeks there have been tests. That threw me into a bit of a panic at first! However they were multiple choice and not too hard, also, no one but you knows what you score anyway.
A lot depends on the people who run the course, in some courses the Educators are very hands on, as GS said, and are always about answering questions and joining in the discussions. In others they aren't as visible and often these courses aren't as enjoyable. I think this one though, as everyone will be starting with an enthusiasm for genealogy, should be a good one.
Sustev, I can recommend the Richard III one, I really enjoyed that.