Complex sentence: There is a common misconception that blanket forts are only intended for young children, but this is completely untrue, as blanket forts can be enjoyed by all ages, including young children, teenagers, young adults and the elderly.
Split into simpler sentences: There is a common misconception that blanket forts are only intended for young children. This is completely untrue, as blanket forts can be enjoyed by all ages, especially teenagers, young adults and even the elderly.