Yes and no, Between chapter 1 and 7, they are between 7 and 8.They are in their second year at the Academy. I'll explain to you.
- In this universe, they start the Academy at 6 years old, spending their first year the year they turn 7. A school year at the Academy is from May to March. So, for example, Haruto turned 7 during his first year , and will be 8 during his second year.
-To retrace the timeline, here it is: Haruto and the others were born 3 years after the Fourth Shinobi World War, and started the Academy at 6 years old, turning 7 during the school year. For example, Shinachiku and Hanami turned 7 on June 9th, and Hitomi and Haruto turned 7 on July 7th. Then, during the same school year, their first school year, in October, Hitomi died. In November, Sumire came to Konoha, met Haruto, and joined the class mid-year, in November. The first school year ended in March and the second school year began in May, during Chapter One. The characters were therefore about 7 and half , some already 8 and other not.
-Iwabe is a special case because he is 2 years older than the others characters:
He (8) was in his second year at the Academy when the others had turned 6. Then, he repeated the year, spending his second year a second time in a new class and being 9 years old this time while the others characters entered the Academy and spent their first year, growing to 7 years old during the school year.
Iwabe repeated once again, spending his second year a third time in a new class which is the class where Haruto and the others are. Iwabe is 10 years old because his birthday is on March 21. The others characters will grow up in this year and will be 8 years old.