other modifiers for variables and methods (that would allow modders to make mods easier to make mods. Also: changed height limit (instead of 256: 32, 64, 128, 256, 512, 1024, 2048 blocks).
I think the age doesn´t matter. It´s only important to have some experience. For example if someone makes mods, it´s not important to reach a certain age. I´m 15