I was an only child until I was 5 when my sibling was born.
My twin sister and I had seven years before my brother was born.  
Cool, siblings can be like really good friends if they get along. I'd say me and my sister get along pretty well.
Going from an only child to having a sister must have been an adjustment.
Only child
An only child is a person with no siblings, either biological or adopted. 
Children who have half-siblings or step-siblings, either living at the same house or a different house - especially those who were born considerably later - may have a similar family environment to only children, as may children who have much younger siblings from both of the same parents (generally ten or more years).
Overview.
Throughout history, only children were relatively uncommon. From around the middle of the
about how I'd like to be an only child and how I was bitter towards my sister because she never had to help do the hard chores. It only seemed logical to me to change soul to sole as a joke. Sole brother/only child."
- What to Say - "'What to Say' is about how much and how little sense we make when we speak," Lalonde told SPIN.com. "It's about the multitude of wrong words and the never-ending search for the right