six times magnification should easily get you to 100 yds (and beyond)... if you are having difficulty, it's probably not your eyes (or age) - but more likely low quality optic.
There are lots of threads on this forum (and throughout the internet) with detailed info/reviews... you might want to determine spending limit and go from there (it doesn't have to be a lot - but of course cost is relative).
But to address you question directly - no, a magnifier isn't the answer... in fact magnifying a magnified optic will most likely further distort.
My Simple Life of FREEDOM feels good in My Soul... Good luck CGN Brothers
Originally Posted by FireCloud9
We're screwed. The left was fooled by Obama and the right is being fooled by Trump.