Omg! I don't know how I am going to handle this!

My husbands niece is the same age as me. My husband and I have been TTC since October and we finally got our BFP in Feb and a MC in March, so we are trying again. His niece just moved her wedding up so they could get married sooner. (My thought was because she is pregnant, and that thought killed me!!) Then today, she text me and told me that once they get married they are going to start TTC. I just don't know how I'm going to handle if she gets pregnant before we do. It's not a competition by any means! It's the fact that we have been trying for a while and when we did get it we had a mc less than a month later. Anyone else go through something similar to this? How did you handle it? Did you end up telling that person you had a mc? I just want to sit and cry right now because all I'm thinking of is that she is going to get pregnant before us. Ugh