Goku is infamously killed at the start of the Saiyan arc, giving his life in the fight against Raditz. Goku later sacrifices his life at the end of the Cell Games, opting to stay dead for seven years before having his life restored by the Rou Kaioshin during the events of the Majin Buu arc.
The breach in Wall Maria happened during the year 845. Eren was around 10 years old during this time. Two years later, he decides to enlist in the military with his childhood friends, Mikasa and Armin. Now going back to the year 850, he graduates from the Cadet Corps at the age of 15.
So physically he was 11 but by birth he was about 10. And 7 years between the cell saga and the buu saga puts him at about 17 by birth and 18 physically. So by the B.O.G movie and/or the beginning of dragon ball super he would be about 25 or 26.
Age is a very tricky thing to nail down for certain characters in the Dragon Ball universe, but it's easier for Gohan, who actually grows up on screen. Gohan's birthday is stated to be May 18, Age 757, which makes him 4 years old at the start of Dragon Ball Z. This means that Gohan is 23 when Dragon Ball Super begins.