Sir Ian Holm is not the right age to play Bilbo. Remember The Hobbit takes place sixty years before Lord of the Rings. Bilbo was close to Frodo's age when he went on his adventure.
Ah, thats right what was I thinking? You never know though, they could make him look younger...But it would work too if they found someone that looked similar to Ian Holm (thanks for the name, my brain went dead ) But I'm sure Peter Jackson will make everything work out just fine, he always does
May the wind always be at your back and the sun always upon your face, and the winds of destiny carry you aloft to dance with the stars.
Bilbo Baggins in the beginning of The Lord of the Rings was one hundred and eleven, but he looked as he did when he took the ring for himself. The ring gives you long life. Ian Holm played Bilbo when Bilbo was supposed to look fifty not one hundred and eleven.
I heard Elijah Wood was offered the role of the young Bilbo, but he turned it down. He said he thought people would still think of him as Frodo, and that he wanted to move on anyway.