It is hard to find the reasonable written very old characters. In the pop media characters with declared advanced age are often still behave like teens (which make me doubt in their intelligence level). But it is also hard to write them. But I'll try...
My girl character is formally nearly 90 years old, but actually only 27 (most of these years were spent in stasis).
My guy character is formally nearly 90 years old. But... he has some... peculiar properties both of body and mind. Particularly, his body getting aged much slower than plain, not upgraded human body. Also his brain has less degree of neuroplasticity than usual, so his personality changes less with time than in average (hard to say more without spoilers). So his biological age is 30-35, and psychological age is like 40-45. But in the same time he remember events from all his lifespan, so he has very reach life experience and knows a lot about people and world.
There will be both younger and a bit older characters, but not too much older. At the first place, just because it is too hard for me to imagine how would think the person > 100 y.o. 0_o