Not sure why it's so unbelievable? A friend of mine that I used to work with was a monster in the gym. Does a lot of competition, and at 5'-10" and 186lbs, I personally saw him working out with 90lb dumbbells. He benched 340+lbs and squated over 700lbs. He moved down to Texas to go back to school, and would enter some competitions. He said he was getting smoked by a lot of guys in his weight class.
The original poster could be built well for lifting, and be a really lean 125lbs. If he needs to lie over the internet to impress people, that's his problem.
Mark
