Regular guard or southpaw ?

Hello everyone, I have a question, I have been training Muay Thai for about a month now and when I tried it first my coach taught me how to stand properly in defense and told me to put my left leg in the front which means I am in regular guard but today during training I tried switching and putting my right leg in the front and I found out that I was more stabilized and that my kicks had more impact. Is it normal to find out I may be southpaw a whole moth after and does it erase the little progress I have so far ? Thank you ☺️