In 845, when Eren was just 10 years old, the "Colossal Titan" suddenly appeared. Large enough to breach the Wall, it allowed other Titans to rampage through the city.
When the wall is destroyed, Eren, Armin, and Mikasa were 10 years old. When they joined the training academy, they were 12. They were 15 when they finished training and joined the Scouts. They remained like that for most of the series.
Eren Jaeger
After his hometown of Shiganshina is attacked, 10-year-old Eren vows to kill all of the Titans. Five years later he's able to start actively pursuing that goal, joining the Survey Corps at the age of 15.
On 844, at the age of nine, Eren saves Mikasa Ackerman after she was kidnapped by the traffickers, until one of the three managed to tackle Eren by almost cloking him to death but he was saved by after the man was stabbed through the heart, thanks to Mikasa.
According to AOT's website, Eren Yeager is 19 years old in this final season. Mikasa Ackerman is also 19.
So, what does this mean for Eren? He could be exempt from the 13-year rule because he obtained both the Founding and Attack Titan from Grisha (and the War Hammer Titan later on), or his supposed immunity could be negated by the fact that he acquired both Titans simultaneously.
Even if a person gains a second Titan shifter power like Eren, they still only have 13 years to live. This is because the lifespan of all Titan shifters is predetermined and cannot be changed or extended by gaining additional powers.
Realizing that Ymir has a will of her own, Eren embraces her and asks her to help him rather than try to order her. As Zeke desperately tries to stop them, Eren asks Ymir if she was the one who called him to the Coordinate, musing that she has been waiting 2000 years for him to arrive.
It's made clear that this event took place in the year 844. By simple math, one can determine that this would mean Eren and Mikasa are fifteen years old in the year 850 when the majority of the story takes place.
This confirmed exactly what Eren saw that caused him to do everything he's done since: he saw the future. Specifically, he saw this moment with Grisha and the Reiss family, including the presence of a future version of himself.
As Armin tries to rescue Eren, the Bearded Titan closes its mouth, biting one of Eren's arms off in the process, and swallows Eren, much to Armin's hysterical horror. It is unknown how Armin survived the Bearded Titan and the others afterwards, but he was no longer attacked after the deaths of his friends.
Eren ate his father when he was 9 years old in Attack on Titan.
The YouTuber estimated the Wall Titans' width to be 12.5 meters and their height to be 50 meters, or around 10 meters less than the Colossal Titan. According to his estimations, there were around 573,084 Wall Titans in the Rumbling.
As the Colossal Titan, Bertholdt appeared beyond the south gate of Shiganshina District, breaking the gate apart and breaching Wall Maria in a single kick.
Eren would learn he was the Attack Titan in Season 1 at 15 years old; however, he was not aware that he inherited the Attack Titan from his father five years earlier. In fact, the Eldians of Paradis, outside of the royal family, did not know about shifters until Eren turned into the Attack Titan.
The tallest Character in Attack On titan is Keith Shadis. Standing at 6′6 (198 CM). The tallest female character in Attack on Titan is Yelena. Standing at 6′2 (190 CM).
Eren is 6″, Mikasa 5'8″ and Armin 5'5″. Some other noticeable growths to occur during the time skip are Connie Springer (5'2″ – 5'9″) and Jean Kirschtein (5'9″ – 6'2″). 9 titans appear in Attack on Titan, all of various heights.
Eren's appearance changes quite drastically when he transformed into the Attack Titan. His height increased to 15 m, his hair grew long enough to graze his shoulders, and his tongue and ears became elongated.
For 2000 years, Founder Ymir waited for someone until Mikasa appeared.
After being brought back to Marley, Ymir willingly allowed herself to be killed and was eaten by Marcel Galliard's brother, Porco Galliard, transferring the power of the Jaw Titan to him.
She transforms into a Titan at 10, spends 8 years or so dominating Eldia's neighboring countries, bears King Fritz's children at 18, then dies at 23 when her own children are around the age of 5.
Because it is impossible for anyone to surpass the Founder, each person who gained the power of the Titans was fated with the "Curse of Ymir" (ユミルの呪い Yumiru no Noroi?), which limited their remaining lifespan to only 13 years after first acquiring it.
Both are technically correct. In the official English translation of the manga his last name is spelled Yeager. In the official translation of the anime, it's spelled Jaeger. So, using either one is pretty much fine.
Before the operation to retake Wall Maria Keith Shadis tells Eren that he first met Grisha about 20 years ago. At this point the attack on Wall Maria which coincided with Grisha's death happened 5 years ago. So Grisha had in fact been inside the Walls for 20-5 = 15 years!