Awesome Ant!
Was there a mango/fruity scent on the skin when you picked it? I found that this is the best time to pick the Glenn...at the onset of that scent...and eat within a few days (left at room temp). I found that if you leave the Glenn on the tree too long after that scent starts, the fruit begins to ferment/sour on the tree.
Nevertheless, the coloration of your Glenn is excellent, so it looks like that fruit had pretty good exposure to light.
My Glenns have not ripened yet this year.
In the past, some of my Glenns can be green (mango shaded from sun inside the canopy) but ripe, which forces me to do the homegrower "sniff" test to detemine when to pick.
Its tough to do the sniff test when the fruits are too high, but I guess you can also do the quarter turn twist test too.
Enjoy!