I'm still very much a biking newbie, but I consider myself an expert on Monster Legs! After 15 years of soccer, mine are certainly two monsters and not shrinking any time soon. I swear I had the terrible pant-waist-gap thing going on by the time I was 10.
Consider the new muscle a trophy off all your hard work! More muscle strength in your quads and calves puts less stress on your knees too, and who would complain about that?
Somewhere behind the athlete you've become and the hours of practice and the coaches who have pushed you...is a little girl who fell in love and never looked back... do it for her.