Back when I was 6 and my father thought it was idea to buy me a bodybuilding magazine to surprise me since he noticed how much I liked watching Conan.

Under 10.  Don't know if I recognized as "attraction" at that point, of course, but I had a definite interest as far back as I can remember.  I wonder what it must have been like for it to simply dawn on some folks at a later age.

Probably 13

I was 18 and started college.  This girl, while not a FBB, she was strong, and muscular, and love to prove her strength to anyone she felt like it proving it to, by outlifting guys in the gym, or run faster.  Once, she beat some poor soul in a pushup contest and she did all of her pushups with one arm.  She was some type of athlete.  It's been so long, I can't remember, but she was never aggressive towards me (well except for a couple of times, which I will not disclose), but was more of like that nice girl next door who always wanted to hug and cuddle up with you.  My friends wonder how could I have tamed such a wild animal because they feared her,and I didn't.  Either I had something they didn't, I was a fool.  Even her kisses packed muscle.  That was a woman.  Too bad she moved.

I guess when I was around 10. I used to fantasize about muscular women, but had never actually seen one. Then I saw an episode of Fear Factor with Tatianna Butler, and then found myself at wpw.net. That's when it began... ^^;

15 and younger 

My older brother use to play football.  Instead of PlayBoy, Penthouse, or Hustler he had Muscle&Fitness, Flex, and Ironman.  I would look through them and was strangley drawn to these females with muscle.

always liked strong women from as long as i can remember.... but got a taste for muscle women in my early teens through eurosport, in the early 90s.

i began to like fbb from 13

i saw some women in ad and i started to like that

about 14. maybe i would have been earlier into the fbb admiration, if it was more coverage of the female muscle scene back in the early eighties.

My first prolonged hard-on (lasting nearly three weeks) was when I was 9. Saw Lynda Carter as Wonder Woman bending a steel bar. She's no FBB, but perception is reality. What I find most attractive about FBBs are their (potential) physical strength, not so much big muscles. I also get turned on by non-muscular women showing great strength all the same.

16-21 I first saw debi laszewski on fitnessbeauties.com and I was hooked

12-13.  I remember going to the news stand and buying WPW and seeing the women.  Must have been the late 80s.  Not to many boob jobs then and to this day I still prefer my FBB's to not have implants.  There were also some female athletes at my high school that  had great legs that I still fantasize about today. 

16-21, I discovered the attraction for FBB, when I saw a video of Susan Myers, on a 90's show, where there some FBB, and the son of Susan on the public. He said that was proud of her mom, of her strenght, so I searched more on the web, and I discovered this world.

16-21

i still remember how my friends laughed at me when they found out fbb's turn me on....

I was definitely under 10 when I was for the first time attracted by fbb's ! I remembered watching contests on Eurosport in the 90's ! When I was 15, I found THE book : "The Women" by Bill Dobbins, with a lot of amazing pictures ! When I first opened this book, it was like a new world of beauty and fantasy !
And then, I got the Internet (God bless it) and started looking for more videos, new athletes...