Okay so this may seem confusing, so I am clarifying it here.
Fang, Yaya and Boboiboy are 16-year-olds.
Ying is a 15-year-old.
Gopal is a 17-year-old.
Thunderstorm, Cyclone and Quake are 15-year-olds.
Blaze and Ice are 13-year-olds.
Thorn and Solar are 7-year-olds.
Timeline throughout this series:
1. Boboiboy leaves, et cetera. He leaves his watch.
2. Pulau Rintis gets invaded by Vargoba.
3. Boboiboy is revealed to be rich as fuck. He gives them a luxurious place to stay.
4. In the cruise, he is revealed to have third tiers and a new watch.
5. Fang and Gopal broke a promise and meddled with his stuff.
6. Boboiboy reveals his fire element third tier and almost kills them. His old watch deems Fang as worthy.
7. They try to talk to him, but fails.
8. He was recaptured, but he fought his way out with earth element's third tier.
9. Boboiboy defeats Vargoba because he wants them out of his life.
10. He kidnaps Fang and tries to train him to use his old elements.
11. Fang escapes back to TAPOPS.
12. Boboiboy is revealed to study Fang's watch to wake his youngest brother, Solar up. The attackers at TAPOPS were his brothers with second tier elements.
Trivia:
1. In the first chapter, Boboiboy had mentioned "there is family he misses". However in the rest of the series, he claimed to be alone on earth. This is true, because his seven younger brothers were in space.
2. Solar is in a coma for two years. (Which meant he had gotten his power watch at the age of 5.)
3. The reason of this coma is because of his power watch. The reason on how Boboiboy first achieved Solar applied the same to Solar. The strain was too much on his young body.
4. Fang has his first tier elements. His brothers had each second tiers. Boboiboy had both first and third tiers, no second because he gave it to his brothers.
5. The rest of it you'll have to wait for Arc 2. :)