Self Imposed Diet! Tips?

So I'm going to try and lose weight. I'm doing the correct way. I asked my mom a couple weeks ago and she said she would take me to a nutricionist, she never did. So
Anyways, instead of writting it in a notebook I'm going to write my plan here and ask you guys for some tips. Write your tips below and your opinions too! it could help! Here's my plan:

Leave all drinks (I usually drink iced tea, and will only drink it when eating with my family), only water (& coffee).
Leave in between meals
Eat little (a cookie or juice a day instead of pizza or French fries) at school when not staying in school because of extracurricular stuff, (I eat when I come home from school)
Serve myself one time.
No desserts :( or extra meals Or candies
Eat more veggies
I'm going to start exercising when vacation starts, since I usually can't exercise because of school stuff.
My goal is to lose at least 20 or more lbs before this year ends.

I weight around 145 to 150 lbs
I'm around five feet tall.
I'm going to 14