Funny i found this post. I was just like you when i started out. I had to stop for health reasons but plan on resuming, in that time I was doubting if it would work for me. I dont have a "success" story per se, but I can attest that when I was PE'ing I felt better about myself. I'm sure if I hadnt stopped and kept working at a routine, I'd probably have my goal reached or at least be closer to it, but dont sell yourself short on ANY positive changes that could be seen in doing PE. I met some cool people, got a lot of reassurance, and so forth.
Not sure is 6 is your BPEL or NBPEL, but either way you are well into the average range dude. They say the average now is 5.6 (not sure how they're measuring) but either way you're ahead of the game. Another thing I have to stress, NEVER underestimate a woman's ability to be a size queen, OR to not know how 7 or whatever number, looks or feels like.
One last thing, make a realistic goal, or make goals in small increments. I have recently been re-thinking my goal, but I only wanna gain a bit over an inch because it's attainable in my head. Im on the walk with you though, still trying to see for myself if I can gain. With that said, if you need to vent or have questions, I'm around a bit, and will be around more in the coming weeks.