Just keep this in mind as you go through the potty training, bite inhibition training and other "stages" of puppy hood- "This Too Shall Pass, This Too Shall Pass". You are going to be fine and these are just the jitters, which indicates to me you are well prepared for what will happen once the pup is yours!
My little Yogi is going to be 12 weeks on Sunday... this is the one month Gotcha Day- I've lost a lot of quality sleep, stressed way too much about potty training, and have bite marks all over my hands because we are learning bite inhibition and proper chew toys, but these are just stages in his total development and will pass since we are determined to train him promptly. It's the moments when he gets something or is such a love bug that blur these other things out of my mind.
Go for it and don't hesitate because with your determination you will sail through the challenging stages and it will be a distant memory in a couple of years!