Tonight is Pesach Sheni, which occurs one month after Pesach.
The historical purpose of this day was for those who were unable to bring the Korban Pesach on the correct date—because they were then Tamei or too far from Yerushalayim—to have a second chance to do so.
Some have the Minhag to mark the day by eating Matzah.
The Minhag to eat Matza is actually tomorrow afternoon/evening, when the Korban would have been brought/eaten.
There is no Pesach Sheni tonight. Whatever there is is only tomorrow.