Oh another SW questions? re: boarding

[Sugar Jones]

So I was just reading that you can't pre-purchase seats. I have two anxiety ridden children that have never flown and are terrified. How do I ensure that we will sit together, I can't imagine not sitting with the kids????

I looked at the early boarding thing and I am more than willing to pay for that, but what are the odds that we will still be able to sit together after family boarding - (which we don't qualify for because our kids are too old)

The two children with anxiety are 11 & 9.