Hmmm... just today i made a plane that can’t get off the runway. you must be pretty lucky for orbit! But it seems that yours may be a little too heavy at the front. if you bring some weight to the back you may get good. As Hvp said, you may have too many control surfaces, but maybe not enough, try either adding or taking them. . I would recommend making the middle section larger, or smaller wings or engines. have a look at the stock craft for a look at how they work. maybe use spaceplane wings, not delta wings, as they offer more controllability regarding center of mass. hopefully this helps.
btw, this is my first post, please tell me if i am doing something wrong, I’m kinda new.