The rough-in for your kitchen sink drain is too high for the installation of that garbage disposal. Your fixture drain (trap arm) is coming out of the wall so high that you had to install the J-bend of the p-trap backwards to get it connected. The backwards J-bend gives you a very deep trap seal which is not going to let the garbage disposal drain very well. Food particles will probably start collecting in the trap because of the deep trap seal. If the drain turns verticle there where it goes into the wall it might not be to hard of a job to correct this. By cutting open the wall and removing a section of the verticle drain and install a tee for your drain a few inches lower. This should allow for the proper p-trap and drain installation of your garbage disposal.