Honestly, I don't know if stuttering causes us to mature earlier; maturity goes hand in hand with each individual's mindset. While there are people like yourself who developed early maturity due to the challenges that stuttering brought, there is also another counterpart of people who simply give up on life because of their stuttering condition. As for me, perhaps stuttering contributed a bit to my maturity, in keeping me calm and clinging to life. Because undoubtedly, it is possible to recover and regain fluency; the evidence is in all the people who have recovered, and not only that, but we ourselves can appreciate fluency in certain contexts. It's just a matter of activating those same mechanisms of fluency and applying them to our daily lives.