SIL just announced

I just got my BFP, which means I'm about 2 1/2 months behind my sister in-law, who just announced a couple of weeks ago. I still have two months til I want to announce, but I don't want her to feel overshadowed or like I'm trying to get all the attention or compete with her or whatever. I know my brother will be happy for me, but I really don't know his wife that well, and would love some advice on how to handle it.