Notable cast of Sonic characters:
Team Sonic
Sonic: 15
Knuckles: 16
Miles "Tails" Prower: 8
Team Rose
Amy Rose: 12
Cream the Rabbit: 6
Big the Cat: 18
Team Dark
Shadow the Hedgehog: Age unknown, created over 50 years ago. Physically never ages, however due to his similarities to Sonic it can be presumed that his physical age is 15.
Rouge the Bat: 18, incorrectly marked as 17 in the Sonic Heroes manual.
E-123 Omega: Date of creation is unknown, can be assumed that he was created sometime after the events of Sonic Adventure 2 as his purpose was to guard Shadow's pod.
Team 'Future'
Silver the Hedgehog: 14
Blaze the Cat: 14
The Robotniks
Dr. Ivo "Eggman" Robotnik: Age unknown, likely to be in his 50's due to his words in the ending of SA2 where he states that he used to look up to his grandfather as a child.
Professor Gerald Robotnik: Unknown.
Maria Robotnik: 12
The Chaotix
Vector the Crocodile: 20
Espio the Chameleon: 16
Charmy Bee: 6
Mighty the Armadillo: 16
Babylon Rogues
Jet the Hawk: 14
Wave the Swallow: 18
Storm the Albatross: 19
Assorted
Princess Elise III: 17
Marine the Raccoon: 7
The Commander: In his 50's-60's. Looks to be younger than Maria in flashbacks.
Chat with our AI personalities
Fiona Fox is 16 years old in Sonic the Hedgehog.
Planet Mobius
Not All the Characters but a Few...
1. Sonic the Hedgehog 2. Shadow the Hedgehog 3. Scourge the Hedgehog 4. Nazo the Hedgehog 5. Jet the Hawk 6. Metal Sonic 7. Mecha Sonic 8. Blaze the Cat 9. Silver the Hedgehog 10. Knuckles the Echinda
To me, I think he started depending on your question is in 1991,where the old cartoon "Sonic The Hedgehog" started.