20lbs lighter in 1month?

I want to be at least 20lbs lighter before July (is that a healthy amount in this amount of time?), which gives me a little more than a month. Does anyone have any tips on work outs for tummy fat and inner thighs? Also what kind of foods should I avoid? by the way I'm a 16 year old girl, I'm 5'3 and weigh roughly 163lbs, which is a lot I'm guessing...
20lbs lighter in 1month?
Post Opinion