Getting Ahead of Yourself

In our advanced Business English ESL class, we have been reading Outliers, by Malcolm Gladwell.  In chapter 5, he uses the phrase, "...we're getting ahead of ourselves."  For those who are ESL students, what does this idiom mean?

Usually, when someone wants to explain something that has more than one point, they have to explain it in steps.  Sometimes, they get to the end before explaining the earlier points well enough.  So, they say, "I'm getting ahead of myself."

• Example 1:   If a scientist was trying to explain the benefits of an experiment, without explaining well what the experiment was.
  
• Example 2: If a child was thinking about all the gifts they would get at his/her birthday party, even before the party happened.  A parent might say to the son or daughter, "You are getting ahead of yourself."  
  

On Freedictionary.com  they explain it like this:  

          get ahead of oneself  Fig. [for someone] to do or say something sooner than it ought to be done so that 
                                                   the proper explanation or preparations have not been made. 
                       
                                            I have to stick to my notes or I will get ahead of myself in my lecture.             
                                            When he bought a new little bicycle before the baby was born, he was getting ahead 
                                            of himself.


I hope this short explanation helps you to understand this phrase better.  :)