Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
EST = GMT-4, I am Central European Time (GMT+1). If you want to play tournament games elsewhere on Smogon, be prepared to learn what GMT is...
Either way, 12.30 pm your time works fine.
Word of warning since you're new, all RBY/GSC/ADV games are to be played on Pokémon Online and not Pokémon Showdown, so make yourself comfortable with that.