As others have already said CC is firmly intended for veterans who know exactly what they’re doing, or at the very least have the operators and resources needed to follow a guide.
A good rule of thumb imho is if you can beat Faust & Mephisto under your own power and deployment order, you’ll probably do well at CC. Not necessarily R18 well, some tag combos are a real pain, but at least well enough to get a not inconsiderable chunk of mats from the shop. And you’ll more likely than not be able to follow a guide if you’re determined to full clear the event.
Operators that can fulfil multiple roles, most notably healing defenders, are very useful; as are operators that can sub for others (Plume sometimes works as a budget Melantha).
Most of the magic happens with selecting tags though, unless you can say “I have an answer to this” you probably shouldn’t take it. Combos are also really important to watch out for, more so than outright risk level.
A risk 2 ASPD increase on an acid slug isn’t awful if you have crowd control or raw DPS to deal with them before they can do any damage, and a risk 1 DEF increase will make them able to get in range, but ultimately do negligible damage and debuffing that won’t matter in the short term or long run. Both of these by themselves are benign, but together they can let them reach and then collapse your front line, possibly taking an already squishy ranged unit with them in addition to your defenders or guards.
Or, alternatively, you can swap your 1 risk enemy DEF boost out for a 2 risk operator defense reduction. This will cause exciting new problems for sure, but manageable exciting new problems rather than a threat to be outright wiped, and as a bonus grant you a higher risk level.
Also, there are practice stages available everyday. They cost no sanity and change daily. It’s only the side stages but it’s still good for learning how to play CC perma stages as well.
All in all though, I wish you the best of luck for your first time playing it, and not to worry too much about getting it perfect on your first go.