Is it time to move on from my Ka?

I passed my driving test in March 2004, I quickly bought an old Citroen AX. I HATED IT. I had never quite grasped how having a decent reliable car can affect your driving confidence and enjoyment before. So the hunt was on for a better car and really a reboot of my ‘first’ car. Enter the Ford Ka!, I purchased mine with a trade in of the AX in September 2004, the car was sooo much better than that awful little AX. For a driver with little experience the Ka not only gave me confidence, but made me appreciate and enjoy driving. Now the Ka was far from new, it is in fact a 96 P reg. This month the Ka will turn over on 100,000 miles and it does feel older now. However like a much loved pet I am finding it hard (especially when I get behind the wheel) to move on. I know its days are numbered and that I should trade up whilst I can, but fear of the unknown gnaws at the back of my mind.