I think if it matters to you, it's possible to do it. However, I also think that often our fears are unfounded when we examine them closely. So maybe take stock of that first. How personal is what you write, and would it really matter to share it with people you know "irl"? What are the potential positives - might you later want to tie your Medium writing to other endeavors with your real name on them? Only you can decide what is best for you, there are a lot of subjective things to think through and it's a personal decision. I've recently started sharing more of my writing on my personal socials and have found that the people I know from outside of Medium are excited to read what I write and see this part of me, and I was scared of that vulnerability but am now glad I did it.