With eight years of experience in Android and mobile app development, I possess the exact skill-set you require for this health and fitness application project. My proficiency in both Java and Kotlin is exemplary, which will be crucial in developing your Android app with 3D models, video streaming features, on app chatting and payments capabilities. With an in-depth knowledge of Android Studio, augmented by my understanding of Python, JavaScript, and Java, I am fully equipped to tackle any challenges your project may bring.
Moreover, timing is one of my specialties; having worked under tight schedules on Android projects previously, I understand the importance of timely delivery. However, approaching this task in a timely manner wouldn't compromise the quality as I also know how to balance speed and precision effectively. My primary objective is to provide a robust and user-friendly solution that aligns perfectly with your vision. Plus, having successfully built applications integrating chat and payment systems like yours before, our portfolio speaks for itself.
In conclusion, if you want an experienced professional who can guarantee high-quality solutions within a specific timeframe without sacrificing efficacy or creativity, then look no further. Give me this project and let's create something that truly leaves a positive impact on the lives of users while augmenting your profitability. Let's work together towards success!