Take a deep breath...let it out...in again...let it out. There. That should start you to relax.
I just went through my first kiddings this week, Thursday and today.
My does were FF, and they both delivered twins without incident.
My first doe was quiet and I was awakened to the sound of her kid bleating on the baby monitor. When I got to the barn, the second kid had just dropped.
Today, at 3 AM, the sound of the second mom was what I heard.
When I went to the barn, she was pushing and making some sounds. First kid came quickly and the second followed within minutes. No knowing if I should help her with the first one because the head was coming out and she was pushing, I let her do it on her own before I intervened. I didn't have to. She did a great job cleaning them and getting them ready for the world. The 1st afterbirth came shortly after that and then the second.
Because I was there I did towel them off a bit and I sprayed their umbilical cords with iodine. They were looking for the teats to eat, so I put them on them and they suckled for all they were worth.
I cleaned up the "mess" and put them on fresh straw, gave mom some hay to eat and she went to town eating it.
Like you, I was worried because of all the problems that I read about associated with kidding. I tried to put that aside and kept telling myself that my girls were healthy, not grossly overweight other than the pregnancy weight, and had good prenatal care.
Nature seemed to triumph in this instance and no problems whatsoever.
Tell yourself that your girls will be fine too, but always be prepared to step in should the need arise.
Best of luck to you.
Oh, I forgot to mention, this goat shares the same stall with the other goat that kidded on Thursday. She and her twins were right there when the second kidding happened. Now some might say this isn't the way it should be done, but my two girls are joined at the hips and are inseparable. If I was to separate them, I know it would cause them far more stress than if they were left together.
First doe visited today's newborns and her twins came to see their cousins too. No problems whatsoever. Not saying this is right or wrong, just what worked for me.
I'm editing this to add...
Both of my girls were first timers and they had twins, so don't always think that the first time is only going to be one!