yes, i get what you're saying. but no matter which side you attach to the batting first, that quilting won't show on the other side. the batting + back will be easier to hand, so adding the top will be easier, too, than it would be the other way around.
start in the middle and work your way out. a little at a time. i know it sounds crazy but it works better that way. you have to roll up the sides tightly enough to help it fit and flow better through the machine throat (the opening to the right of the needle.)
it all takes practice. this quilt is going to be a nightmare because you started with something that was bound to be difficult no matter how much experience you'd had before. each quilt you make from now on will get easier.
i still wish you'd cut yourself a break and at least tie the middle then machine quilt around the outer edges where it'll be easier to handle.