Hello, *name*!
As you know my birthday is coming soon. I would like you to come. The party will be not big. I'll call my parents and few friends. We'll celebrate in pizzeria. Well, you know, the one in the city centre. If you want, you can call someone else. Maybe your friends want to come? I'll be glad to everyone. The party starts at 11 AM. But if you're late, it's okey. I'll wait for you!
With all my love, *your name*!