Why Is It So Hard!

So we are still trying to get Tyler potty trained. We just keep missing everytime he needs to go! I have woken up the past 5 mornings and Tyler has had huge messes. I just don't know why its so hard for us and Tyler to get it all done! I have a potty chart on the wall just like at school. He will read all the steps but when it comes to actually "going," he won't do it! Tyler will be 8 in a few weeks and I just can't take this anymore! I want him to be in underwear and be able to go to the bathroom independently. This is yet another example of how autism can affect your child's life and yours. If it would only just click in his head. I wonder what "pieces" of this puzzle he is still not understanding. I pray this is over soon!!!!!