Hi Sarah,  Your baby is so beautiful.  I am a lover of all corgis but am on my second fluffy pem and think that they are beautiful.  My 2 pems were related and were heat intolerant and here in the south that can be very bad.  I am going to try to squeeze a pic of Randy in that I took yesterday for you to see how he looks.  

Now keep in mind that I clip him myself so that he does not look as good as if a regular groomer had done him.  But you don't want your girl clipped any shorter than 1/8th".  Once upon a time I bought a clipper for my job and just decided to try using it on my other girl.  Since then I have gotten a new one and have a selection of blades.  

The one that I use on most of the body cuts to 1/8th".  He will even be a little cold for about 3 days.  1/4" would be a compromise but despite what people tell you it grows like weeds and the shorter it is cut the faster it seems to grow.  

I have seen posts on this site that described work of bad groomers that didn't follow directions and used shaving clippers and clipped the babies to the skin.  So I think your directions should be of the shortest length that you will allow.  You might even go to Pet Smart or a place where you can stand outside and watch and be ready to rush in and say Stop.  Beware of one that acts like you know nothing and that they know better than you do about everything.  After you get this please feel free to ask questions.

Sarah,  I am so glad that you have someone that is experienced.  She won't be as beautiful but she will be so much more comfortable.  Last year was the hottest year here in AL in the 24 years that I have been her so I cut him short so that I wouldn't have to do it any sooner than absolutely necessary.  My profile pic was taken in about March or April and he was back to his beautiful self.  Good luck and let me see how she looks after her pic. Lois

Great, now she can get in the rain and ditch and not be too hard to clean up.  Take and post a pic of your new short haired girl.