If you have not paid child support or have not been receiving the child support you are supposed to get from the other parent, there is a way of collecting that money later on. It is known as back-paying support, and it's how children can eventually obtain compensation for child support they were supposed to get during their years growing up.
A divorce isn't easy for most people, and the likelihood is that there will be some difficulties that come up with yours. It's likely that you and your spouse will have some disagreements, but if you're willing to work together, you can get through them. If not, you both can go to trial and have a judge determine what happens with your divorce, but that is usually not the best option for anyone involved.