Congrats on your desire to go to the suck at an advanced age. I for one, am also 40... as are a number of us here. However, I went many many years ago. We had a 39 year old SGM in our class... he was recycled, but I heard he eventually made it.
1. DO NOT QUIT. PERIOD.
2. DO NOT GET INJURED. PERIOD.
3. MEMORIZE the RANGER CREED, by heart, every stanza, before you get there.
4. DO NOT CHOKE SLAM THE YOUNG BUCKS AROUND YOU.
Seriously though, there are some on here, that work at Pre-Ranger and are current RI's that will advise you better than I can.
The hardest part for you will be keeping yourself in the mind set. There's some silly shit that goes on... you have to be able to tune it out, and stay motivated. Your peers will test you, call you gramps, the likes... just roll with it.
Injuries suck. At our age, the body does not snap back. Ranger School sucks, and it sucks for many days in a row, with no rest. It takes a toll on the body, even a young body. So, use your ultimate weapon... Your maturity and your mind.
AS far as I know, the APFT is a deal breaker. You have to meet the standards or you will not get in. Show up WAY early, Very short (bald) hair cut, no facial hair, proper uniform, paperwork in order, and be ready to give 100% and then some.
Don't be a spotlight Ranger.
I think, my old ass covered everything I can think of. Someone will be along very shortly to address things for you. Thank you for your willingness to do this... keep us posted as to your status. Some of us old guys will be pulling for you!!!
As EP said... Intro's are SOP.