The rigging can be a little daunting the first time out, but with some patience and scheming it can be done single handed. Sailing the boat is not that hard. The boats are well balanced from a steering perspective, the sheet loads on the main are handled very well by the 8:1 or 9:1 block systems and the asymmetrical spin flies like a huge offwind jib (in the simplest of terms). If you’ve been sailing a lot on other boats you can get these boats around without too much hassle. Obviously, the more extreme the conditions become –the more skill it takes (as with any boat). It would be prudent to when and where you start your sailing. Singlehanding requires a deeper look at conditions and recoverability (righting solo, getting the boat sorted, etc.). Obviously, learning in a vacuum with no others around will slow the improvement process.
Having said that, racing these boats at the pointy end of the fleet is difficult and requires a lot of practice. Racing is always more demanding – getting 80% out of these boats is easy; 15% can be gained by time on the water and the last 5% requires a dedicated training/coaching/fitness program.
I do agree with PGPs idea of getting together with others. It is what makes sailing more fun anyway.
As for a starter cat… the positives are high performance, latest designs, growing fleets for racing, latest and greatest gear, easy to manage on the beach, sexy. The downside is price point for a “starter cat”. The second hand market is growing, but you will still spend some cash – so it depends on what you want it for, how you will use it and how much you are willing to invest. Multihulls give you the best “bang for your buck” as related performance, but that does not mean they are cheap

Where are you located?