Speaking from experience, you are only rushing the lessons if you are not following the lessons (and the 50% rule). In other words, there is no specific amount of time each exercise should take, but make sure that you are really understanding what the lesson is and doing it as correctly as you can. That may mean you have to take your time on observation or rereading the lessons before continuing. Some of the excercises are very straight forward and quick and others take time. Lesson 2 is a great example. Organic shapes with contour lines is not that time consuming but the texture exercise and dissections should take you a lot longer. I have rushed things at times and it really shows up in my submissions. Also, you may personally find some exercises more difficult (or easy) than others. Everybody is different.

Most, if not all, of the exercises from Lessons 1 and 2 have links at the bottom in the "student-made recordings" section to videos where ScyllaStew has recordings of her working through the material. I often find that she gives a very good example of just how long this work can take, to help those who may be rushing get a better sense of whether they're holding themselves to an unreasonable standard.