Utilize those Fat Quarters with this dynamic pattern that includes a youth-size option (64" x 80") using 11 Fat Quarters, and a double-size option (80" x 96") using 18 Fat Quarters.

This pattern is relatively simple, but deals with fabric cut on the bias, so I consider it a Confident Beginner pattern.

The Fat Quarters also NEED to be at least a full 18" wide. If you have a FQ bundle sold by a fabric company, they're machine cut, so you should be good. If they're cut by hand by a fabric shop, then hopefully they cut them a tad wider than 18" to give you some wiggle room.