We learned this is first grade.

Thank you all for coming I just want to let you know that I'm sorry I didn't show up it was Siri's fault she didn't remind me about my book signing.


Has no one heard of ending a sentence with a period and beginning the new sentence with a capital letter? 

How about: Thank you all for coming. I just want to let you know that I'm sorry I didn't show up. It was Siri's fault. She didn't remind me about my book signing.