Royal Rainboom part 1

Rainbow dash awoke to a door bell ring which was quite strange because she was taking a nap on her favorite cloud.
"Who is it?" Said rainbow dash rolling out of her soft fluffy cloud.
"Mail mare" said derpy" derpy is that you?" Asked rainbow yawning.
"Who else would it be? And I have mail for you from the princess-" said derpy as she was interrupted by rainbow dash shrieking"the princesses what do they want with me? Did I do something wrong? The sky is clear, right? Pfft what am I saying they clearly want to see me, do they? Do they derpy?!" She screamed as she grabbed derpy.
"I don't know, I just have this letter from princess Celestia?" She said shaking as she handed the letter to rainbow.
"Thanks derpy, but why did I hear a door bell?" She asked taking the letter.
Derpy giggled and helled out a doorbell in her hand as she flew away.
"Whaaa-?" Rainbow asked starring at the strange mare as she flew away.

Rainbow opened the letter, it said...
Dear loyal Rainbow dash, Luna and I have had some rather blank days at cantarlot lately and we where hoping that you could possibly preform a sonic rainboom to lighten things up a bit...
Sincerely, Princess Celestia.
Rainbow had at first a rather shocked expression which was followed by a cheery "awesome!"
This was her chance to show how incredible she was in front of every pony in cantarlot and nothing could go wrong...
Right?