You have two novels going at once? And you’re thirteen? Am I talking through some kind of space-time continuum to Young Author Sara? Because that’s exactly the type of person I was. *high fives*
So, it’s fitting then to give the kind of advice I would have given to Young Author Sara, which is:

This industry will throw a lot of rejections at you, but if you want it, persistence is the only difference between a published author and an unpublished author.