That is super, and especially since your son is 14. What talent and thinking ability!
I think you will find the compartment to the right of the machine to be handy for all those things we need when we sew: seam ripper, scisssors, extra thread, needle threaders, etc.
Now if he will make you an extension, you will have the best of all worlds. Do be sure he keeps a somewhat wider piece of wood to the front of the extension as that makes feeding the fabric easier. It needs to be well sanded and if he uses polyurethane on the wood, it makes it easier for the fabric to slide. (My husband made one for me.)
Cricket