In that case you may have been able to feel it. This kind of "prostate massage" is quite risky, for a number of reasons including infection, damage to local tissue, etc. If you have symptoms suggesting a prostate problem, make sure to take them up with a doctor. Given your age, prostate cancer is highly unlikely, but prostatitis, or something else, would have to be evaluated.
Think you understood wrong, was not poking at abdomen. Was felt through anal insertion :s
Probably not. The prostate is located below the bladder and behind the front part of the pubic bone. It would be very difficult to isolate this spot by poking at your lower abdomen. See the entry on the prostate gland on Wikipedia for an anatomical illustration of the location of the prostate.