should i replace the timing belt, not because of mileage but because of age?

Hi! this is Bo with Car Genius! Hi there! Sounds like an awesome car! Fortunately, the 3.9 has a chain and those are considered non-serviceable. The truth is that you can replace it but if it's not making noise you're fine. With only 19K, I bet it's good! If you have any other questions feel free to give us a call at (877) 913-1554