There is NOT supposed to be a gap between the wing panels. If they are already glued in place you're going to need to try to slide some filler stock (balsa) between them and get that glued in place. Right now the entire load is on the dihedral braces. (Pete had it right) ALWAYS dry fit parts before applying glue to make sure they fit properly. This gives a chance to make adjustments if needed to make it right.

On site help from an experienced modeler is obviously a plus for a first time assembler.