At the temple of Avo can you keep giving money and getting "The Gift of..

It is a one time thing, unless you use the hero save exploit on the Find the Archaeologist quest. Go to the Temple during the quest and donate about 48,000 to 53,000, as soon as you hit (A) to donate the gold, start rapidly pressing the (A) button until the donate screen comes back up, if you did this quickly enough, you should have kept the gold, but the donation still counts. Check your age and see if it has changed. If it has not, donate 1 gold coin and that should do it. Once you have done this, hero save and reload the save you just created, you'll start over with lower age and you can go back to the Temple and do it again. You can lower your age to 18 by doing this.
Be sure and save before you donate and make sure you keep your gold using the (A) tapping trick, and only do this for the reduced age and potions you find in these areas. If you try to get multiple weapons, or the Paladin title, you could cause your game to freeze.