A computer won't necessarily be slow just because it's old.
Today, £1100 will buy you a Macbook Air with an 8-core CPU, 16GB RAM and a 256GB SSD
In 2015, £1100 brought me a desktop PC with a quad-core 4GHz CPU, 32GB RAM and a 250GB SSD
(Yes, obviously, there's been inflation, comparing a laptop to a desktop is a little unfair, the newer machine's RAM will be faster, one includes a built-in screen, etc etc etc)
Today, £1100 will buy you a Macbook Air with an 8-core CPU, 16GB RAM and a 256GB SSD
In 2015, £1100 brought me a desktop PC with a quad-core 4GHz CPU, 32GB RAM and a 250GB SSD
(Yes, obviously, there's been inflation, comparing a laptop to a desktop is a little unfair, the newer machine's RAM will be faster, one includes a built-in screen, etc etc etc)