100k miles is a little early for trans failure, but it’s 17 years old. So, what’re ya gonna do?
I have seen transmissions go well beyond 100k miles and never have any service done to them. I’m not saying you shouldn’t change the fluid regularly. Obviously, you should. But 100k miles is a little early…although I have seen them fail sooner.
Even with fluid changes, clutches wear out. If you’ve never had to replace a transmission, keep driving the car and at some point you will. But, changing the fluid and the filter is the best (the only) thing you can do to try and make them last.