835. Not Starting Pesach Early

118:11 A son who is at a Seder with his father is required to lean (even if his father is also his teacher - OC 472:5) but a student at a Seder with his rebbe does not lean. (It is actually forbidden for the student to do so, but if the teacher gives him explicit permission, then the student is obligated to lean - Mishnah Brurah 472:15-16.)

119:1 Even though one can make Kiddush and eat while it is still day on every other Shabbos and yom tov, adding from the weekday to the holy day, on Pesach this is not the case. This is because the mitzvah to eat matzah applies specifically at night, like the Pesach sacrifice, about which it says "eat the meat on this night" (Exodus 12:8). Similarly, the commandment to drink four cups of wine applies specifically at night. Since the cup used for Kiddush is one of the four cups, one may not make Kiddush until it is definitely night (i.e., after the stars come out - MB 472:5). One should put on his kittel (a white linen robe) and sit on his seat to make the Seder.

It is a mitzvah to give the children things like almonds and nuts so that they will become curious and ask why things are different. They will then be encouraged to ask about the matzah, the maror and the leaning. A child who had reached the age of education - meaning that he knows about the sanctity of yom tov and understands what is being said about the exodus from Egypt - is also given a cup to drink from. (It's not problematic if the child is not given a cup because, according to many authorities, the four cups were not instituted for minors - MB 472:46, Shaar HaTziyon 472:60.) It is customary to fill one cup more than there are people dining. This is called the cup of the prophet Elijah.