Our thoughts are not His thoughts, and our ways are not His ways.
Whatever the Lord will have happen here will happen. Regardless. Since you have the opportunity now to go to school, I would say go for it. They have online classes that you can take, as well as doing some in college. If you have another baby sooner than later, will that really disappoint you? You have been given a new life to care for and cherish, so if your plans are interrupted for a time, praise God. and if they are not, praise God. He works all things for the good for those who love Him and are called according to His purpose. Just remember to be content with whatever you have been given. Whether a big house or small. Another child or not. Or a career or being a mommy and caring for you little ones.