Aquella guitarra era de mi padre
You CAN put
1: Para mi quinceañera yo ago una fiesta muy grade solo para mi.
Translation: For my fifteenth birthday, I have a huge party to celebrate me.
2: Cuando yo cumplo los quince años, mis padres hacen una fiesta de quinceañera y invitamos a todos.
Translation: When I turn fifteen, my parents have a huge party and invite everyone.
3: Para mi quinceañera muchas personas me dan regalos muy bonitos.
Translation: For my fifteenth birthday, my friends and Family give me really nice gifts.
Hope this helps :D
4th one. Carmen caminaba a la playa.
The first one is using the nosotros form. The second one is using preterite but using the yo form. The third is using the you form.
The 4th one is saying it was a continuos activity and it was talking about a specific person.
