Do you also have the tendency to speak too fast when you are standing in front of an audience? People tend to speak fast when they are nervous and most people get nervous when they need to speak in front of an audience. The thing is that if you speak too fast, your audience will have difficulties to follow you. The feedback that may get afterwards is that they will tell you that they could see that you were really enthusiastic about the topic (as they try to be nice to you).
But, did they understood the key points of your presentation? If you ask different members of your audience to tell you what the top three key messages of your presentation were, you would probably get a range of different answers. They don’t dare to tell you in your face that you were talking to fast and couldn’t follow precisely what you were saying so they make up the three key point based on their best estimate.
It is important to take your time and don’t speak to fast. Look at the body language an interactions of your audience to ensure your audience continues to follow you. Have a look at the book that is part of the public speaking kit with more detailed tips and tricks about this including what to do against the nerves (to avoid speaking too fast).