I remember the inventor of the TRX saying his grandmother uses it when he was on Fox News. There's no upper age limit, but as always you should consult your physician before starting an exercise program for the first time, and not dive in too deep to start. Because the TRX is not a weight machine, and only uses a percentage of body weight (from 1% to 100%) it is suitable for people of almost all fitness levels.
You have not said too much about yourself so I don't know what condition you are in other than your are physically active, I doubt the military fitness program would be suitable, but I have no idea what you are capable of so it could be the best for you.
To find out where to start i'd advise you to look through the DVDs and Guides on the page linked bellow. There are videos of the exercises contained in each, so you can see what you think would be most suitable. Two good places you could start would be "TRX Biomechanics: Healthy Back" and "All Body Xpress Guide & DVD".
http://www.fitnessanywhere.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Fitness-Guides-Programs
Then look for the bundle most suitable for you on this page. Such as the "TRX Professional" or "TRX Home Training Bundle"
http://www.fitnessanywhere.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=PB
The TRX is tested to over 1500 lbs, so even that guy in mexico who is the worlds heaviest man could use it. You will just need to make sure you have an anchor point that can support your full weight. You could use the "TRX X-mount" bolted through a strong support beam on either your ceiling or wall. If one of your children is good at DIY you could enlist their aid in setting it up.
Hope this helps you make a decision.
Max