Hi there. I think that is a reasonable goal. I would definitely run this by your parents though as you are young and obviously, they buy your food and help plan your meals.
I would think in terms of how to eat healthy and often weight loss follows. This means dropping the processed things out of your diet like chips and crackers and obviously the sugar items like cookies and such. Instead, have a piece of fruit for a snack or a hard boiled egg or protein bar. Keep your portions smaller at meal time and try to stick to lean protein, fruits and vegis.
Exercise for a half hour at least 5 times a week where you get your heart rate up (where you can talk but are breathing hard).
Good luck and let us know how you do!
At 13, your body isn't fully developed, so I agree with specialmom that you should enlist help from your parents.
Try to make sure you have a protein with every meal or snack. Protein can include yogurt, a meat, cheese, peanut butter, egg, etc. Make sure you eat plenty of veggies. Make water your drink of choice.
And yes, make sure you get at least 30 min exercise most days.
Thank you. My mum is all for me losing a bit - as long as I do actually eat and not starve myself.