SIL might be offended my husband told his best friend first

I am currently 5w pregnant. We found out about a week and a half ago. My sister knew right away because we tell each other everything. For everyone else in the family we’ve planned out telling them. My family will find out at Thanksgiving. We wanted to tell as much people in person as we can. Last night my in laws came into town for a concert and at dinner we told my MIL and FIL. When we told them, we let them know that my husband’s best friend already knew. He was talking to her on the phone and it slipped out and really both of us wanted her to know sooner as we are very close to her.

My MIL asked when we would tell my SIL and we said we wanted to tell in person so it could end up being Christmas before she knows. Personally I don’t have the best relationship with her and her and my husband aren’t super close, so I don’t really want to have to share with her if we happen to have a miscarriage in the next few weeks. When my MIL got home she called me to let me know they were home and how great of an evening it had been and how excited they were. She also mentioned that, though it is our choice, my SIL might be offended by husband’s bf knowing first. Neither of us really reacted on the phone, talked about it with husband afterwards and decided to leave it up to him when to tell her. Now I am struggling with guilt though. I still feel like I’d rather her not know, but don’t want to strain our relationship further. She tends to be competitive with me, doesn’t like that I can cook and sew, and I just know that me having a baby first could be another source of strain. I am 31 and she will be 31 in January, but as far as me and husband know she isn’t planning on trying for a while yet. I feel like me having lots of experience nannying and with baby’s compared to her is going to add to this. Please give me some advice or reassurance of how to deal with my SIL.