In my experiences, I've come to realize that the difference between second age and third age LI's is not that much. There is a slight damage increase, along with a few other minor buffs. As was stated earlier, in the first comment, first age weapons are very hard to come by. In my opinion, they are rather useless. In the time it would take to find a first age symbol, you could have nearly maxed out a second and third age LI both. Just stick with what you love!
R7 Champion- Vladimar| R6 Blackarrow- Truebow
"He who lives by the sword, dies by the sword."