Combine graham cracker crumbs with sugar and butter in a bowl. Firmly press into the bottom and up the sides of a large 10.5" pie dish or into bottom of a rectagular 9x13" pan. Use the flat bottom of a glass to help even the surface and compact the crumbs.
Pour lemon jello into boiling water and stir until dissolved. Place into refrigerator until cooled to room temperature.
In a large bowl beat cream cheese with sugar, lime juice, lime zest and vanilla with an electric mixer until very smooth. Pour cooled jello (must be room temperature!) into the cheese mixture and beat until well combined.
In a separate bowl beat heavy cream until medium-stiff peaks form. Gently fold whipped cream into the jello/cheese mixture and mix until combined.
Pour into prepared crust and refrigerate until set-- about 2 hours. Serve chilled with whipped cream and lime wedges.