can i run with 32 gb of ram on my 2012 mid macbook pro

Each slot on that model MacBook Pro supports up to an 8GB DIMM maximum, provided you install the exact correct spec DIMM -- not faster, not slower.

You can mix sizes if you like. This runs ever so slightly slower than a matched pair, but the difference is not noticeable in real-word applications.

NO.

The only MacBook that can even generate addresses to talk to 32GB of RAM is the top-of-the-line 15-in 2018 model.

All others can not address that much RAM, and Retina and later models cannot be upgraded at all.

No.

MacBook Pro: How to remove or install memory - Apple Support

All you need to do is buy RAM that matches the max specs for that machine. It's PC3-12800 DDR3 SDRAM @1600 MHz. You want 2 sticks of 8GB or a 2x8GB set. This is exactly what you want. The exact max specs and the best quality you can get:

Crucial 16GB https://www.newegg.com/Product/Product.aspx?Item=9SIA7253VC9532

Mushkin will be have the price at around $95 but Crucial and Corsair make much better quality RAM. All memory is not created equal! I would only put the best stuff in a premium machine like a MBP, iMac or iMac Pro. Leave the budget stuff for cheap Windows notebooks and custom PC builds.

With budget RAM you take the risk of receiving a bad pair that will lead to your Mac crashing a lot. Of course some of them some are good but when you buy quality like Crucial or Corsair you will never have any issues!

OWC also sells quality stuff including SSDs for your Mac. Like the saying goes you get what you pay for.

OWC.net gets recommended here every day.

Crucial.com gets recommended here often, but they are very conservative and do not appear to have a lab full of Macs.

I buy from DataMem.com, and have been very happy with their ability to provide the right modules, first time every time, or your money back.