I did as a child.
Also, If I was writing in a notebook for example, I turned the book over and wrote on the inner back page instead of the front, and wrote right to left.
To this day, if I get a magazine, I flip it over and start reading at the back page.
I am also dyslexic though so that may impact it.
Despite both of these foibles, I am well educated and in a professional job.
With regards to the best plan for your DC, I don't know. I had years of being forced to hold the pen in my right hand, until one teacher with compassion took me under his wing. (Small village sch in the 80's, he taught me for 5 years, and will always be the teacher that made a huge difference to my life). It took years of practice to develop legible handwriting. But it's now something I am complimented on all the time. Don't make a big issue of it though.
Maybe model to your DC the right direction to write in. So you write the first letter, then get her to copy, pointing on the paper where to place it. Then when she copies the second letter, point out to place on the right side of the first. Etc.
But if she starts getting upset, distressed etc just stop. Sept isn't far away and school will have their way of developing her skills.
Let her enjoy reading, writing etc. From there the rest will fall into place. But if it becomes a bone of contention at this stage it could take years to break down.
Ultimately don't worry too much. There are loads of us lefties in the world and generally we get on ok.