Might this be too much for a 13 years old, 8th grade of middle school?

That sounds fine...just make sure that you blend in everything nicely, and that your face is not a complete different color than the rest of your body! (had a friend do that once, not pretty!) Also, make sure you pick a color for your foundation, etc. that will match your skin tone well and also not look cakey. As for mascara, make sure its not clumpy and stickyyy! Other than that, if I were a sub I would think you were just another student!(: Hope this helped!(: