That is an ambitious project for a first project. But entirely doable. You will learn a lot doing this project.
I agree with Paul that a Wemos D1 Mini plus battery shield and an accelerometer are a better choice because the Wemos already has WiFi and it's a smaller footprint than the Mini plus ESP8266 board. (The Wemos can be programmed using the Arduino IDE).
A DS18B20 temperature sensor against the skin would give you a relative temperature. (Skin temperature is always lower than the body temperature).