When should the timing belt be change on a 1995 Buick Century LTD, V6 engine, and how much would it cost?

I have a 1995 Buick Century LTD, with a V6 engine, and 105k miles on it. Does the timing belt needs to be change now? What is the estimated repair cost for this service?When should the timing belt be change on a 1995 Buick Century LTD, V6 engine, and how much would it cost?
3.8L

Doesn't have a belt. It has a chain that never needs changing.When should the timing belt be change on a 1995 Buick Century LTD, V6 engine, and how much would it cost?
That engine in your car, weather a 3.1 3.3 or 3.8, does not have a timing belt, it has a timing chain. The timing chain under basic operation most times will outlast the car and not need replacement.
it is not a belt, it has a chain

estimate complete $400.00