Human_Beans: I would like to have a 45-year-old human in my initial party. All the characters the game allows you to create are all quite young, and you cannot change the age in the game options. How can I do this?
01kipper: Starting age is fixed (although will vary depending on race and class). The only way to increase age in-game is to have the spell Haste cast upon them (which is a 3rd-level spell and not available at the start of the game).
"Gold Box Companion" may have an option to change a character's age (I have never used it myself).
Otherwise, hex editing may be your only option (I've never done this myself so I can't help you there either), besides simply using your imagination and ignoring the number on the screen.
I highlight this as the right answer because although I have not yet tested either proposal, I believe that even where they prove inconclusive, there is no other better alternative. I'm not that familiar with such deep changes in game files and in general I'm a lazy guy when it comes to these things, so worst case, in the end, I'll use the weapon that no one has so far countered yet: fiction.
Thanks for the suggestions.