yes. (and you should only even want to do GOMAD if you're really skinny).
Though since you're (i assume) a teenage boy and you're about to do SS, your parents will probably need to readjust their perceptions of how much you eat. Soon they'll probably start letting you drink whatever you want in the hopes that you stop eating all the food in the house.
finally... learn to search. say to google:
+site:startingstrength.com gomad