Best of luck!
Your first all grain batch will also be a test of your mashing setup. This means you're working with unfamiliar equipment in addition to unfamiliar procedures. Lots of fun, but also lots of new ways to screw up.
Amylase enzymes denature fairly quickly; you have about 5 minutes to get your mash temperature down to where you want it.
In reality, you have a bit longer...more like 15 min.
Given the high degree of modification of most modern malt, starch conversion can happen fast - within about 30 minutes.
Conversely, most brewers run off their wort too quickly - for maximum extract efficiency, you want a slow trickle of wort. This also helps combat hot-side aeration.
Unless you batch sparge, in which case you can run off as quickly as your system will allow.