On a clear day, toddle off for a drive into the country.
Plan a route that is not likely to stress you, and take it easy.
You need time to get to know the vehicle, and to relax into your driving. There is no substitute for experience.
Any 12 year old vehicle will have its faults and show signs of wear. However once you know how to get the best out of it, you will be happier with it. My car is similar, and as I battle with the worn clutch, or declutch to get into a troublesome gear, I smile at the thought of how cheap my motoring is compared with those who have new cars.
You might need advice from an experienced driver about how to cope with some of the problems of your car.