Help!? I need an excuse!!

Help please!! My BFF's baby sprinkle is this weekend. It's a brunch at a restaurant with bottomless mimosas. All of the women there know that those are one of my favs and I'm not about to turn down bottomless mimosas 🍾 however..... just found out I'm pregnant! 🎉 So what do I do!? Its my besties day and I don't want to take away from her and I'm only 3 weeks and I don't want to tell anyone. My husband and I want to keep it between us for a while. What do I say!? I need an excuse aka little white lie about why I'm not drinking!