In Star Wars Tales # 11 (Han Solo Cover comic), there's an interesting story that shows Leia when she was 12.
Bail Organa was instrumental in disarming Alderaan. Remember the line "Alderaan is a peaceful world. We have no weapons!" ? Well it seems that after the Clone Wars, to warrant the best possible public opinion, and safeguard the world from Imperial invasion, Bail became the planet's Viceroy and proposed disarmament. Palpatine would therefore have no cause for stationing a military force there to "keep the peace" if they posed no threat. It was a very benign and subtle form of passive resistance - quite both a risky and clever position actually - until the Death Star came along.
Tarkin himself visits Alderaan in this comic to meet with Bail Organa. He's accompanied by Daala (who was working on his Death Star project in the Maw Installation out near Kessel and conveniently near Despayre and Wookiee slave trade routes) and Tarkin is accompanied by his own Mon Calamari slave, Ackbar. The story is very respectful of continuity.
Leia is about 12 at this time and "accidentally" sprays Tarkin while watering her plants from a balcony.
I think Tarkin was there to inspect Alderaan's disarmament for himself, as he so wanted to wipe the smug smile off Bail Organa's face, but he had to be polite and return kindness with kindness, as Organa had outmaneuvered him. Too funny in a pre-Death Star time frame.
Anyway, Leia had a holo of Padme - that is how she knew "she was beautiful, kind, but sad..."
She also had a best-friend and handmaiden, Winter, all in one. She grew up with Winter from at least the time she was 10. Winter was brought up for public service, much as how Padme had been involved with "the legislative youth corp" on Naboo. It was apparently common for aristocratic children.
Leia had rebelled against the high-society primping of the upper class however, and even cut her own hair short when she was 12. A wig was made for her to compensate for her appearance until her natural hair grew back, but borrowing from what she might or might not have known about her mother's decoys, she dressed Winter up as herself with the wig, and ran off with an older boy who was courting her. Just like mom, she was very young. "I was 12. His name was Pablo. We were both in the Legislative Youth Corps." In this case, Leia's young suitor's name is unknown. But the Princess was a little handful. She was indeed born to be a Rebel, hehe.
I mention this as I wonder what the live action TV show might feature.