For a new soldering project,s a full-on (and expensive) mechanical keyboard is not really what I'd start with, but it's totally doable (to be honest, the first thing I ever soldered, was an expensive amplifier, and it worked for me, so I can't really speak)
That said, cherry switches are pretty "forgiving", and relatively easy to solder, so as long as the controller is already put together, it won't be too hard.