Happy birthday, my dearest mother! You taught me how to be courageous and compassionate, you always loved me unconditionally even when my mood was transitional. From all my heart, let me tell you that I love you more than life. My mom is the sweetest woman in the world, you are beautiful and that’s true. read more
To figure this out, leave the other subject out of the sentence. You'll be able to figure out what's right by how it sounds. “I's birthday” is clearly not right. The pronoun needs to be possessive without the addition of the possessive 's. read more