Altho small, and female, you should be aware that muscle is heavier than fat, and that as you lift, ride and run, the stronger muscles will enlarge somewhat and the fat component will shrink somewhat so you could concievable gain some weight. Not talking about a lot, but 3-5# is not unreasonable. With a little time and lot of effort your power output for your weight could allow you to outride a lot of male riders up hills. That is true of half a dozen or so young ladies in my area. You won't end up looking like the weight lifters on TV either as it takes extraordinary efforts to do that
for men and women both.
Steve