How do I tell someone who just had a miscarriage that Im pregnant?

So I am 7w2d and I found out I was pregnant the day after Thanksgiving. I was scared at first since I am only 19 but now my boyfriend and I are excited. We have our own place and were actually already planning to move into a two bedroom already. So we are doing okay. But my aunt has been ttc for years. Her boyfriend has a lot of thyroid issues so they have been trying IVF. Well my aunt got pregnant at the same time as me. We were going to have a baby at the same time. And I was scared but excited. But I still hadnt told her. And then I found out she miscarried. So I finally told my mom two days ago that I am pregnant and because we are having a big family Christmas breakfast together today she wants me to tell my aunt. She swears she will be happy for me but I know she will be heartbroken. She has been trying and then I popped up pregnant. It doesnt seem fair at all and I feel so bad. I dont want her to be the last to know but I also dont want to hurt her feelings during Christmas. I feel like everytime she sees me I am going to be a picture of what she almost had... like I will be where she would have been if she hadnt miscarried. So what should I do and how should I tell her? I really need advice. Please help.