How old is your CPU / processor?
One quick test is the 'Generation' of the Intel Core processor.
Core processors have a brand (i7 / i5 /i3) followed by a model number (8700 / 7700 / 6700). The first digit of the model number is the 'Generation'.
The Intel Generation minus one roughly equates to the year the processor was introduced.
So, for example, a Core i7-6700K processor is a Gen 6 processor, and was first introduced in 2015.
Here's a table with more samples:
How old is my computer?
You've heard of 'dog years' (dog's age x 7 = human age).
'Computer years' are about 15 to 1 vs humans. So a 5 year old computer is ~75 'human' years old.