Well done Holland it sounds like you're going to be fine to me, take the 20 miler steady and you'll be well set.
I did my first 20 mile run on Sunday 24 August and felt good, did a shorter 12 miles this Sunday just gone followed by some intervals on Tuesday am, suffering now with achilles and calf trouble and I have a half marathon this weekend. I think I'll still do the half but hold off on intervals after that, I always seem to have calf problems for a few days after interval sessions. As much as I enjoy speedwork it's not worth it at this stage.
Hopefully another couple of 20 / 22 mile runs to come if I can keep injury free.