Is there a way to find out a wireless internet network password from a computer that is already connected to it?

i hope im phrasing this right. my macbook arrived today and i need the password (the 26 digit number/letter code) for our home wireless network. but the paper it was on has been misplaced by either me or my roommate. i’m currently connected to the network on this computer but i can’t find the password anywhere on my computer. is it possible or should i just wait til she gets home and reset the password from the main computer?