You've got this!
"When do I call myself a stepmom?" "When do I show up for events?" "When do I get involved in logistics and planning?" When do I... when do I... when do I? Questions that all went unanswered, as I had nobody to ask. Without fail, one of the big ones came up each year up in time for Mother's Day.
Whatever past pitfalls you've experienced on Mother's Day as a biological mom or stepmom, remember that you can change it just by how you choose to think about it. We create our own reality. We all matter in our child(ren)'s life.
"A kid can have two moms because in my eyes the more people that love her I'm happy!"