From experience I agree with Chrispy, photo editing isn't a problem on any modern system. A fast processor will help slightly when applying complex filters but almost any multicore system from the past ten years can do the job passably if it has enough RAM.
For video longer than short snippets, you'll eventually want a lot of CPU and a lot of disk space. But if you're just getting started you may want to wait a bit on getting too spec heavy. The actual editing process doesn't modify the source material in real time, it just creates a virtual cue sheet of where to pull data from the source material and what effects to apply, and then previews it for you in the same way. Depending on what types of projects you get into and how many effects you're trying to apply, at some point you'll get a feel for which parts should be built in the master file, and which parts should be created as smaller sub-projects, rendered out, and then imported into the master. You don't always need to build your larger projects as one project file.
I'm using an old i7-3770S and I can render an hour of 1080P/30 in about 80 minutes in a sustained encode, or about one minute of a complex snippet in 2-3 minutes.
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