Kind of hard to tell with the deer in that position... but I'd say definitely mature... at least 3. I see some roundness to the belly and the brisket (while not hanging dow) looks full. That rear leg is well muscled down to the knee as well.
Hard to tell overall body shape without a broadside view.
**My completely UNexpert opinion**
"When a hunter is in a tree stand with high moral values and with the proper hunting ethics and richer for the experience, that hunter is 20 feet closer to God." ~Fred Bear