Answer:
1 day before: It's the day before my birthday and I can hardly wait! I chose out a really good looking outfit for my birthday and I also decided I want ice cream cake. All my friends will be there and we will play games and have fun!
on the day of your birthday: I'm finally (?)! I bet my cake is gonna be delicious! My friends are here and we are about to get in the pool then I'm gonna show them my cool toy that I got from my parents for my birthday! Today is the best!
P.S. the question mark means you can put whatever age you want.