That will help when he stanRAB next to Martin Freeman as Thorin is taller than Bilbo who is probably only around 3'6". He does appear to be too young though as Thorin was getting on a bit being 195.
Also there are 60 years between the Hobbit and The Lord Of The Rings but Bilbo doesn't age in those years thanks to the Ring. He still has the appearance of a 50 year old Hobbit which is roughly the equivalent of a mid thirties human. Freeman is definitely the right age bracket to play him.
