I think its a given that age does make a difference to gains. For example an 18 year old and a 30 year old with similar genetics and training as hard as each other - the 18 year old would see better/quicker gains right?
Question is why? Is it testosterone levels?
FYI I'm 32 and trying to start... again...
The example of the 18 and 30 as in comparing one person to another is never good measure of comparison.
There should absolutely no difference between you at 18 or at 30, as long as you have taken care and exercised safely to start with, this will determine how well you go picking up the iron again at 30 and continue into your senior years, 60~70.
With regard to your genes, our bodies are just carriers of our genes and it is the genes that wire our brains and shape our bodies to their purposes.
It's why we think of sex so much.
But I reckon (and this might go over the heads of some young people)the key is maintaining a youthful body composition, high hormone sensitivity and the right activity patterns and levels, because our genes don't know how old we are.
Going hungry sometimes could signal our genes to turn on the repair and maintenance mechanisms, just some strategies I'm using as a tool to last a little longer.
As an aside, Once you stop thinking about sex I reckon your genes will start deserting the vessel.
It sucks getting older, especially if you stop moving.
Wise Bazza is quite correct about it.