maria wrote:
"A MacBook Pro from 2012"
Is it a retina MBPro or a non-retina model?
How much memory does it have?
If it's a non-retina, you can upgrade the RAM (to 8gb) and the drive (to an SSD), and it will handle El Capitan quite well.
But if it's a non-retina with a platter-based hard drive, you might be disappointed in the overall performance after the upgrade. The SSD will definitely fix that.
An SSD is easy to put in, takes 15 minutes with the right tools.