Welcome to the Club!
We all have learning gaps and your student will too.
I'm sorry if that was a shock, but I'm sure if you stop to think about it you'll realize it is true. We are - none of us - perfect!
All students, whether they are in homeschool, public school, or elite private school have gaps. The important thing is to know which gaps will matter and which are less vital.
When do gaps matter?
Certain subjects like math and language arts have components that build on each other. Anytime one level of learning builds directly on the last the gaps are vital to fill. Other subjects like social studies and history are less pressing because as the topic changes so do the content; you can learn about one period without knowing too much about the previous period.