charger extension

Hi, I recently bought a new Macbook air (Retina, 13-inch, 2019). I have a Macbook Pro (15-inch, 2009), its charger is functional and in perfect state, I bought it in 2016. I wanted to know if I can use the charger extension of the 2009 Macbook pro in my new Macbook air, it fits perfectly in the new charger but I don't know if it can damage the battery of my new computer.