I really hope they wouldn't make him look younger in it. It wouldn't look natural.
To be perfectly honest, my expectations of the anniversary special are very low. Even with a good script and a 90 minute long episode (which could very well be the case), there is no possible way to make it work. Or maybe there is, in which case I'll be pleasantly surprised. But the fact that it will be in 3D and half animated makes me shiver in terror. Besides, the anniversary specials have always been slightly inferior to any other episode, so it doesn't seem like such a change.
I'm more looking forward to the Big Finish special. That one will surely be epic!
"Once, I was a real turtle"