In case you are referring to growing up in Vietnam during that conflict, you might look into When Heaven and Earth Changed Places, by Le Li Hayslip. It is not fiction however, but a true life autobiography about her growing up during the war in a small village, and being involved with both the Vietcong and the Americans at that time.
I don't know whether you think this is too adult, but certainly The Things They Carried focuses on the lives of young adolescents who are plunged into fighting in the Vietnam war and how they grow, mature and develop (or not) as a result. In one of the stories, there is also a young woman who begins to change rather drastically as a result of her exposure to the war.
If you are looking for young adult literature about growing up during the Vietnam War era, I've listed two novels below that my students have enjoyed reading.
1. When Zachary Beaver Came to Town by Kimberly Willis Holt. This novel is set in 1971, and one of the main characters, a young boy, must deal with his older brother being deployed to Vietnam. The novel is appropriate for 6th or 7th graders and contains a lot of humor as well as references to common activities and struggles from the time period.
2. Fallen Angels by Walter Dean Myers. While this novel is easy to read, it does contain quite a bit of language; so some school districts place it at the 10th or 11th grade reading level. It follows a 17-year-old through his deployment to Vietnam but also discusses the soldier's younger brother back home and sheds light on the racial tensions that existed throughout the war. The author's older brother was killed in Vietnam; so he writes from a specific and knowledgeable background.
According to my research, here are some choices you may want to check out regarding growing up during the Vietnam War.
Memories Are Like Clouds is written by Diana J. Dell. The setting of the story is during the 1950, but moves into the future, describing a brother and sister who die in Vietnam. The relevance of this book may depend upon when you end the "growing up" period and when the siblings to go Vietnam.
This poignant baby-boom story, filled with memorable characters, is a fond remembrance of growing up in small-town America when life seemed simple.
Another book, dealing with this topic is:
The Ghosts of Vietnam: A memoir of growing up, going to war, and healing by Jim Stewart. The protagonist, Jim Stewart, has a childhood in the '50s and '60 filled with baseball, learning to play guitar and tromping through the woods, in Maryland. A terrible event occurring the day of his graduation motivates Stewart to join the war effort, enlisting in the army and traveling to Vietnam; the year is 1966.
I did not include books about Vietnamese youngsters growing up in the war. Additional novels are highlighted in the sources shown below. I hope this helps.
My favorite book as a teenager was Teenspell: Stories, Articles and Poems From The Scholastic Writing Awards. It was a paperback published in 1973 and I'm sure it would be near impossible to find. It had some stories about the war and some just about being a kid during the 60's and early 70's. Being written by kids, for kids made it a wonderful read! (Probably not what you are looking for but now I have to find a copy!)
Great suggestions, thank you!