This chart will give you a better understanding of how to properly determine your Elf or Dwarven age. Please understand that while your character might be 300 years old, they still only have the knowledge and training of a 39 year-old human.

Elves
Age-------------------------Appearance------------------------Knowledge/Training
17---------------------------------10-------------------------------------------10
34---------------------------------20-------------------------------------------20
118--------------------------------23-------------------------------------------26
229--------------------------------27-------------------------------------------34
312--------------------------------30-------------------------------------------40
451--------------------------------35-------------------------------------------50
589--------------------------------40-------------------------------------------60
600--------------------------------60-------------------------------------------70

* An elf ages more rapidly the closer he gets to the end of his life. In appearance and knowledge, an elf will age 20 years in half the time.


Dwarves
Age------------------------Appearance------------------------Knowledge/Training
17---------------------------------6---------------------------------------------6
25---------------------------------10-------------------------------------------12
30---------------------------------12------------------------------------------16
40---------------------------------15-------------------------------------------22
50---------------------------------18-------------------------------------------28
70----------------------------------25------------------------------------------35
100--------------------------------34------------------------------------------44
130--------------------------------43------------------------------------------53
160--------------------------------52------------------------------------------62
180--------------------------------60------------------------------------------70

* A Dwarf will retain his strength and vigor even towards the end of his life. It's not until the last couple months of his life that his body will start to show the signs of age. His eyes will bulge and become cloudy and moving will become harder and pained. Once this happens, he knows he only has a couple months left to live.