in a medium bowl, stir together the graham crakers and sugar. stir in the melted butter until combined.
take out 1/3 cup of the crumbs and set aside for later.
press the remaining mixture on the bottom of a 9x13 inch pan.
refrigerate the crust while preparing the rest of the dessert.
in a large bowl using a electric handheld mixer or in the bowl of a electric stand mixer, beat together the powdered sugar and cream cheese until light and smooth.
mix in the vanilla. pour in the cold heavy cream and mix on low to avoid spatters until the mixture starts to come together.
increase the speed to medium high and mix until mixture is thick and fluffy.
spread a thin layer of the cream cheese filling over the chilled crust, about 1 1/2 cups of the mixture.
layer the sliced peaches over the top of the cream. dollop the remaining cream over the top of the peaches in large blobs and spread carefully to cover the peaches completely.
spread the cream filling all the way to the edges of the pan so that the peaches are well sealed inside the cream (otherwise if prepared in advance, the air can make the peaches turn an off brown color).
sprinkle the reserved graham cracker mixture over the top.
cover with plastic wrap and chill for at least 2 hours or up to 12 hours before serving. cut into pieces, scoop onto a plate and serve.