dont let that get you down though. as long as you train with progressively heavier weights over an amount of time long enough for your body to adapt and grow to accomodate the loads placed on it, your muscles will grow, and become stronger, and become bigger. but dont take my word for it, try some heavier weights for less reps, about 8-10 is good, and up the weights when you can perform about 12 reps with good form, and your muscles will steadily grow, no matter what sex you are.