My son is currently 31 weeks old and I juuuust discovered Wonder Weeks book after a friend’s recommendation (I wish I knew about it much before!). So I read all the preface and skipped first few chapters about Leaps 1, 2 and 3. According to the calendar, my son should be somewhere between Leaps 5 & 6 right now, but I decided to start reading from Leap 4 chapter just to see if he covered it all and I was amused that just now, in the recent 2-3 weeks, my son completed most of the milestones for the Leap 4 and is not even close to the milestones of the Leap 5. Is that normal?? Can it be a sign of a late development or anything?