Some suggestions to make it easier for you, not telling you to, but it'd help.
Try doing what you did here, and add to it, women, like men, have a limit to how big they get. They won't get as muscular ever, in eternity with eternal life, as big as this for example elee0228.deviantart.com/art/La…
Never. Female muscles take on a different shape then males, theirs are smoother, more rounded. They don't jut out as much.
You should try drawing some muscular men, with your current style it'd seem to fit more on a man, just try it, you might like it.
And to make it feminine, it doesn't gotta be some hulk, strong, but gentle, show some imperfections, some body fat on the ass, the hips, and thighs, the chest/ armpit area and legs, places it stays around even in alot of muscular women, the female form isn't rough, it's generally smooth. You, in order to have good anatomy, gotta have some body fat, somewhere, people with 0% Body fat would die. They would need to CONSTANTLY be in-taking more than enough energy, and if that stops, they die instantly because they can't store the energy.
It'd also help to have the body parts fit together, have the hips be wider than the legs, as they are in real life, have the breasts be part of the pectorals, not just nailed on top of them, have their abs not concave into each other, but smoothly dip in between each other, ect.
I like this very much. The character is reconizable, but with your own take on the character. I like that you were able to add muscle mass and definition, while keeping the character recognizably feminine and plausible. Very nice work. May I ask what tools you used to put the piece together?