This is the basic cultural perspectives of the average citizen of the Republic (with some specifics detailed.) This is what the average Sunaian believes. You, of course, may make your character believe whatever they want, but keep in mind that this is the general cultural background and how your character's actions should be viewed.
During one of the first elections, one party ran on the campaign of "no more children soldiers." The traditional 12-year-old Genin Academies were disbanded and considered atrocious. 18 is when a new shinobi becomes a "Genin" now, ready to face the world and the responsibilities of being a soldier. However, of course those who were trained prior to the law are still allowed to be in the ranks and train rigorously.
All in all, most people in Suna understand the need for a Shinobi fighting force and generally support them; but no longer at the younger age.
You can have a younger character, just keep this in mind.
The water shortages are always something on the minds of the people, so water is very precious. Inventors constantly look for new ways to find it, politicians always declaring they can generate and save more. Water is the one universal worry all Sunaians have.
Technology is seen as the future of saving their food and water problems. They embrace technology at every turn, particularly when it's meant to make living in the desert easier.
Freedoms and Liberties
All are equal. This is the core belief of every Suna citizen. Whether or not one group likes another is different, but they will always respect their right to exist and be different.
Bandits and Criminals
Nobody truly likes crime, but it is something of a necessary evil in the Republic. Despite their support during the war, there is still quite a bit of unruly, uncivilized people in the Westlands. While it's important to protect the innocent and to convince these people to integrate into society, all-out war against them is not something most people consider to be wise.
While other nations are important for imports and exports, Suna citizens tend to be very isolationist in their views. Self-sufficiency is something that they all strive to achieve, including being able to live off of their own food and water. However, Suna citizens do not view any other nation with any particular animosity.