Welcome to the WL&D Community and thank you for asking your question. In doing a little research, your current weight of 123 lbs at a height of 5 ft is within normal limits. The range is somewhere between 94.72 - 128.01 lbs.
May I suggest that you talk with your parents, your cheerleading coach and ask them for some guidance in how to achieve your goal .. although I might suggest you change you goal to 5 lbs .. and see where you are, how you feel and then decide on the next step .. to stay there or lose 5 more. 111-112 is in the middle of the range so truly believe you wouldn't want to lose more than that.
Like mericat said .. check the BMI calculator .. believe you're currently around 24%.
You didn't say what you eat .. so I'm guessing .. and suggesting a few simple changes. Try eating lean proteins (turkey, chicken or fish before beef), fresh/frozen fruits and vegetables (watermelon, apples, mangoes), small servings of complex carbohydrates (whole grain breads, multigrain cereals, wild rice), vegetables (brocolli, green beans, beets, lettuce) and be sure to get your dairy products in.
You already exercise quite a bit, but we can all benefit when we "mix it up". Ride a bike, go swimming, play tennis, dance, do aerobics or pilates .. our bodies get used to a routine .. like cheerleading 4 x a week and abdominal exercises ... so in a while we don't get the same "benefit" as we do when we "mix it up". It's called muscle confusion and keeps our bodies functioning at a higher metabolic rate.
Also, be sure to EAT; don't skip meals. In fact, 3 small meals and 3 snacks tend to keep your metabolism working.
Hope you'll stay involved in the community and let us know how you are doing. And .. run these things by your mom, dad or coach .. and see if they find these small changes reasonable.
Very best wishes ..
Sweetie,
Your weight is fine. Why do you feel you need to lose 20 lbs. Check the body fat calculator in this site and see what % you come out at. If you are 20% or slightly less that is perfect. BMI is not what you want to look at nor is the fashionable weight or clothing size.