[Loredweller]

The max of age is 65.
You can lose 10 at the Chapel pf Skorm - only once, AFAIK; there's no quests here to employ Hero Save;
However, you can use Hero Save exploit to decrease your age in the Temple of Avo (on Find Archaeologist quest; not on Knothole quests, don't be deceived, there Avo's Temple is outside of the quest area). If you do it, you may stay young forever - if you have maxed your char before that; the number of years here seems to depend, besides the amount of donation in gold, on how many points you have to have to the completely good alignment, so you may have to become more evil to get younger here - if not other way then eating Chicken (5 Evil for every Chick). In TLC (don't know about initial Fable) you aren't restricted to the area, so you can bring a bodyguard or two to the Chapel of Skorm to shift your alignment a bit. It's said you need at least 200 space to become Good'er; i'd rather guess it's 500 to get all 10 years (i myself never have; max 9, min 5).

P.S. I, it seems, was wrong about the Chapel of Skorm. Even being a Necormancer i managed to become 18 years old here - however, using Hero Saves with purpose to do it at Temple of Avo... Nonetheless, it seems that you may lessen the age in the Chapel after becoming Necromancer.