How Old Is Optimus Prime In Human Years Novels & Stories

Glancing into the mirror of the new vanity he had someone bring yesterday, I watched his eyes follow my movement. Ever since I 'moved' in with him, the room had changed quite a bit. I would like to think that there was a more feminine feel to it now. "I'm actually in my prime years." He pursed his lips, pretending to be offended. I doubted he was with that sinfully decadent smirk on his lips. Prime? If 900 is considered prime years then I don't know anymore. "What about Granny Ada or Rora?" My curiosity got the better of me. How old would Granny Ada be if she was his grandmother? Over 1000 years old right?