First heard about it at age 18 and was intrigued.
First met someone who had tried synthetic DMT and never broken through at age 20.
Met world respected pioneer DMT psychonauts and saw the entire contents of their Notes from the Underground at age 25. Okay now it was driving me nuts. Grrrrrr.
Got my hands on a CD of the entire history, 1992 to 2008 of the Entheogen Review and inside found Noman's tek and his addendum and finally had DMT at age 41.
For those of you younger folks who think you waited a long time, just a reminder (and yep, this has been hashed over here a lot before) that I had to wait 23 years.

It was worth the wait.
Needless to say, I can only speak for my personal opinion here and I am indeed a member of an ill culture and living in a ultra built up urban, high crime area, where many folks are awesome and oriented towards family, religion, neighbors and community,. . . real bridge builders and folks I have had over to dinner many times. So, I guess this is where I apply my opinions on age.
I feel that the ideal time to begin sincere work with DMT is somewhere between 25 the late 40's. By 25 the brain has quit all its' major growth and huge changes and all the fontenelles have sealed up - :lol: , that is to say, you no longer have any holes in your heads!
I would encourage folks to NOT wait until midlife has passed. If you are in your late 30's to late 40's and are considering it, now is the time in my opinion. For many folks this is approximately the halfway point in life. Most child-bearing and some rearing is over, the body is beginning to change in ways that confirm in a fundamental way that youth and life are NOT eternal, midlife issues rear up and folks seem to find themselves thinking about their pasts and their current concerns or traumas and realize that perhaps they are not going to have infinite time to do their work, etc.