Stutter disappears completely when reading out loud (in public).

Stutter disappears completely when reading out loud (in public). Hey all, I want to share something with you and hope you can give me some insights on this matter. So, I have had a mild stutter since the age of 8/9. I am currently 21 years old. Now the thing that I still can't comprehend is that when I am reading something out loud, let it be in public or all by myself, I don't stutter at all. Whenever I am asked to read a few paragraphs out loud in class, with all my classmates focussed at my speech (which can worsen the anxiety for some), I don't stutter at all. Normally I have a few annoying words on which I always tend to stutter while talking but when I am reading out loud I am 100% fluent, even on these words. I notice that my breathing pattern during my speech is much more synchronized, calm and in harmony as opposed to when I am speaking. Also, I am way more relaxed in my brain, less thoughts, more calmness, when reading out loud. It's important to note that this is not something that is occuring to me recently, I have had this happen to me ever since I can remember. I still haven't found an answer to why this is ocurring. Since I am 100% fluent while reading out loud it seems to me that there is nothing wrong with my neural ability to produce (fluent) speech. However, the fact that I do have a mild stutter when talking makes me believe that something psychological is causing me to stutter. Could be social anxiety (which I have) or bad past experiences with talking situations. I don't know. What are your thoughts on this?