But why are you getting such weirdly formatted time data over the Serial monitor, instead of just getting it over NTP directly? You don't have to poll every second for the time, it can keep time quite well, and then you just print the current time on your display.
Do you just have the one matrix? You've only got real estate there for displaying around one character at a time, so it's not going to be easy on the eyes...if you had 4 or more, you could setup a scrolling display that would be easy enough to read, perhaps using the Parola library.