I'm fairly young (23) and have just started with brain enhancement.
Started by stopping the things that I was doing that were actively harmful (alcohol, caffiene, fried food, white sugar and nicotene are sort of the "5 deadly no-nos") and getting myself on an organic, nutritious diet.
Followed that with a month and a half long body cleanse (it's amazing what cleaning your GI tract out will do for you, as well a clorophyll for the blood, etc.) and then adding in nutritional supplements like zinc, vitamin C, magnesium, calcium, vitamin E and essential oils. I'd just started adding in Acetyl-L-carnitine, DMAE, ALA, and vitamin C ester when I found this site.
After a bit of poking around here through the anecdotal evidence and what I though to be the more sober, safe approaches to nootropics, I decided to add piracetam and Alpha-GPC to my regime. LifeMirage's idea of adding one nootropic at a time seems especially important, since I have found that even adding multiple nutritional supplements to my diet all at once can shock my system into rejecting otherwise useful nutrients.
Have been doing piracetam and Alpha-GPC for about a week now. The first few days were kind of rough (felt really overstimulated, which I corrected my reducing my Alpha-GPC intake), and am now very satisfied with the effects of piracetam, particularly the unexpected ones on mood and motivation.
Also, thought I would mention the Bee Pollen is an excellent supplement (provided you're not allergic to bees...!), and it is fairly cheap. Lots of B vitamins and such, in a fairly absorbable form.
Haven't had any problems with my being young and taking piracetam. Don't expect a drug-like difference though, it's best if you're already dealing with a body that is fairly clean and smoothly running so that you can notice the subtle, synergistic effects that it has with all of the other ways you are already being nice to yourself.