Is this English to Spanish correct?

Dear Maria,
Today I'm going to write a letter to you about my daily routine from morning to night. Before school, I wake up at 6:30 A.M. and brush my teeth and get dressed. By 6:45 I am ready to eat breakfast. I am very sleepy at this time. Then I go to school, and after I come back in the evening, I first undress, at 4:00 P.M. Then I eat a snack, and get started on my homework. By 9:00 P.M. I brush my teeth, put on my pajamas, and lay down to sleep.

Querida María,
Hoy voy a escribir una carta a usted acerca de mi rutina diaria de la mañana a la noche. Antes de la escuela, me despierto a las 6:30 de la mañana y cepillarme los dientes y vestirse. A las 6:45 estoy listo para tomar el desayuno. Estoy con mucho sueño en este momento. Luego voy a la escuela, y después de que yo vuelva por la tarde, PM me desnudo en primer lugar, a las 4:00 Luego de comer un bocadillo, y empezar a trabajar en mi tarea. Por 21:00 Me cepillo los dientes, se puso el pijama y se acostó a dormir.

I've sent the link to your question to Sra. One thing I'll tell you right now -- go back in and put the accent marks where they belong!! If you don't know how to do that on computer, let us know.

1. In the works of Frida Kahlo, once can see the extreme happiness she felt. -False

2. José Martí died in a battle against the United States. -False because I think it was a battle again Spanish troops?

3. In Mexico, most of the celebrations come from Incan traditions. -Not sure

4. In the U.S. one can see some Hispanic traditions with a religious origin. -T?

First of all, beginning the letter with "Beloved Mary" would mean that you are on a first-name basis. If she is about the same age as you, or in your family, it is odd to use the formal "usted" rather than the familiar "tú." Aside from that, I'll check the rest of what you have.

Hoy le voy a escribir a usted OR Hoy te voy a escribir a ti...
me cepillo los dientes (no reason to use an infinitive here, but a conjugated verb)...y me visto.
estoy lista (you are feminine, not masculine)
Tengo mucho sueño = better for I'm sleepy
después de volver = much easier here with an infinitive
This is an incomplete sentence: Luego de comer un bocadillo, y empezar a trabajar en mi tarea
Plus, without proper punctuation (the period at the end of the preceding sentence), I thought this was part of that sentence.
me puse...me acosté

Main question here: Are you telling this in the "historical" present tense or are you to use the Preterit? Being consistent is always best.

Sra

For the 2nd part:

3. Incas in el Perú, Aztecs in México.

Sra

Yes, the English to Spanish translation is correct.