How am I going to have 2 girls?

I’m 30+5 weeks pregnant with another girl. I’ve already got an 8 year old now who is very sensitive. She hates when we yell at her or just raise our voices. I literally don’t know how I’m going to raise 2 girls that I know are going to fight as this new baby gets older. My daughter has a friend over right now and they started bickering and the friend was blaming my kid that she did something. I flipped bit and raised my voice saying we are done with video games tonight and it’s time for bed. I then went to my husband to just vent which he’s a life saver and came and is now sitting with them so I can just get away and go to bed myself. I just feel like an ass to my kid because she didn’t do anything. Then I started thinking how the hell am I going to have 2 girls that I know are going to fight like this? It’s inevitable I did with my sister, my sister in laws do. I guess I’m just assuming rather than waiting for the situation to happen, but I just don’t know what I’m going to do. I just needed to rant/vent more. Thanks for reading