Can I upgrade RAM on this Macbook Pro 13" mid 2012?

Depends. If it's a Retina model, then no. If it's a non-retina model, then yes.

click here ➜ Identify your MacBook Pro model - Apple Support

Models 9,1 and 9,2 can be upgraded. Models 10,1 and later cannot.

click here ➜ MacBook Pro: how to remove or install memory – Apple Support https://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_Pro/Upgrade/DDR3_1600MHz_SDRAM

Whether its worth it at this point, is the real question.

yes, that is the LAST MacBook pro with user-upgradeable RAM. can be upgrade to 16GB MAX.

users recommend this mac-centric vendor to provide great advice and service:

https://eshop.macsales.com/upgrades/macbook-pro-13-inch-mid-2012-2.5-ghz

HGMac wrote:

Thanks it's a non retina, and you can get OWC in UK.

Then it can be upgraded to a maximum of 16GB.