Need computer advise

so I'm VERY new to editing footage from my GoPro (4k 60fps), so I'm looking for a bit of advice here. I'm looking at an older used 2012 iMac
Intel Core i5 Processor 2.7GHz
4GB SDRAM RAM
1TB 7200RPM Hard Drive
27-Inch Screen, AMD Radeon HD 6770M

I know I can upgrade the ram and likely will to atleast 16gb.

Otherwise, as far as ease of workflow and being fairly issue free while working am I likely to be with this iMac working with my goPro Footage on FPC?

IMO I think that with this computer setup you may have difficulty to handle 4K video files. Perhaps with proxies, low resolution, little effects, no composing , etc... you "could use it" . But if you want the superb Metal2 fcpx power you'll need a Mac with both better graphic card and processor.
I'd recommend you have a look to old Mac Pro 5.1 revamped with RX580 and xeon processors. OWC have a lot of them a very nice prices
Jose

I have a 2015 rMBP and can edit 4K, but not multicam, and it starts to bog down if I start adding too many effects and MotionVFX templates. For simple edits, it works OK, but great, but works with 4K from a GH4, Osmo, Phantom 4, iPhone XS. If you're serious about editing, you'll want something newer and more powerful. I'm looking to upgrade mine this summer sometime, maybe the fall.

Dot Prod wrote: so I'm VERY new to editing footage from my GoPro (4k 60fps), so I'm looking for a bit of advice here. I'm looking at an older used 2012 iMac
Intel Core i5 Processor 2.7GHz
4GB SDRAM RAM
1TB 7200RPM Hard Drive
27-Inch Screen, AMD Radeon HD 6770M...

4k H264 from a GoPro is highly compressed and difficult to edit smoothly. IMO a 2012 iMac is just too old and slow for that, unless you transcode everything to proxies. That itself will take a lot of time and space.

IMO the best used machine for that is a 2017 iMac 27. It has a Kaby Lake CPU and the decode/encode performance was improved by about 2x from the 2015 model. You can possibly get one for about $800 on eBay. Even if you got one with a rotating hard drive or Fusion Drive, it would still be vastly better than a 2012 model.