I don't really grow Catts, but I can say that you always want to time your re-pots to root growth (you want the orchid to have started putting out roots (I've heard 2 inches long is a good rule of thumb, some prefer shorter, & some longer... etc), emerging from it's newest lead(s)). I would also say that Spring is probably a good time of year, in most cases, esp. for an inexperienced person...
In the Spring, the daylight is getting longer, it's warming up, and everything is coming to life, including most orchids... So that is usually a good time to re-pot, because all of these things are signaling growth... but it's still important to make sure there is active root growth before you re-pot... (That's the most important thing – root-growth – (IMHO), even if repotting can't be done in the spring, for whatever reason)
So, if anyone more experienced with Catt-types comes along, and says differently, then by all means, take their advice, & ignore mine!
Lol, I know a decent amount about Phals (certainly not everything, & not nearly enough, lol), but I'm fairly new to Catt-types, and there is always something to learn..