Starfire Blaze’s age growth from top left to right;
1; Age 7:
Starfire bore a very strong physical resemblance to his father, Sunburst and like his mother, Starlight Glimmer, he was incredibly magically gifted. His parents wanted to provide the best for their son knowing what his potential was and not wanted him to follow the same path as his mother. However due to severity of the retribution the former Changeling Queen Crystallis, Starlight could almost never come out in public and lost everything she had worked towards since Twilight took her in.

Worse, this mutual hatred carried over to her eldest daughter Luster Dawn and youngest son, Starfire Blaze. Starfire’s sister was totally blacklisted from receiving a formal education anywhere in Equestria and was forced into hiding along with her mother as everypony knew Starlight had a daughter. They however didn’t know she had a son and this was the reason why he was sent to Celestia’s School for Gifted Unicorns. They however never imagined that in addition to magic, his signature talent was that he could raise and lower the sun without losing his magic in the process. Princess Celestia took Starfire in under her wing as her newest personal protégée and it was at the young age of seven Starfire began his education.

2; Age 14:
Starfire proved to be a very quick study and caught up to the significantly older Princess Flurry Heart and Pumpkin Cake who were three and four years his senior. Still he befriended them both as well as Pumpkin’s twin brother Pound Cake and were great friends. Starfire was fiercely loyal to all his friends, but especially for the young princess as she was his first friend and unbeknownst to her, Starfire had started to develop feelings for the filly and it started to cause problems.

Starfire’s attachment for Flurry would cause him to borderline explode in rage at those whom mistreated her and even stand up to Flurry’s parents and the other royals if he he felt that they weren’t treating Flurry fairly. When King Sombra with the help of his old friend Radiant Hope retook the Crystal Empire, Starfire even when as far as completely disobeying Celestia and snuck off to rescue his best friend and her parents from what was certain death.

By the end of it, Starfire was able to not only save Flurry and Cadance, but the with their help, the whole Crystal Empire as well. Unfortunately, Flurry’s father fell protecting Starfire and his daughter from Sombra’s furry, especially after a fierce Mana Sword duel, Starfire managed to strike down Radiant although she managed to leave two permanent scars on the teenager’s body. One on his left eye and another starting from centre chest and arcing upper left and in a desperate act of defiance and defence of Flurry’s life, he stood up against Sombra but unfortunately lost his front right leg and nearly died that day.

3; Age 20:
Now a grown stallion, Starfire had finished his schooling five years prior although he was still learning from Celestia about a wide range of subjects. He also had been learning the art of Mana Sword combat from Princess Luna and better means to control his emotions. As by the old traditional unicorn laws of duelling, Starfire won Radiant Hope’s sword and took it as his own. Only in the hooves of a very powerful unicorn or alicorn, such weapons were absolutely efficient and deadly and required a personal apprenticeship to effectively master and control.