New to this

Hi,
My name is Jill, I am from Louisiana and I am 24 years old.
This is my first time ever trying to loose weight. My son will make 1 April 10 and I would like to loose 20lbs and start a healthier meal plan for myself. If anyone has any recommendations on exercise I would greatly appreciate them! I would love to have a flat stomach, toned legs, and a nice bubble butt . Also, I do take aderral and unfortunately it curbs my appetite.
This app would like me to have 1,200 calories a day but I think this will be extremely tough since I usually only eat about 600 a day. Anyways, if anyone has any tips I would love to hear!