The time period between childhood and the teenage years is called the preteen or tween years. Kids are teetering between an increased level of independence and still being a child. On top of that, hormones are kicking in and bodies are changing.
10 Year Olds
At this age both boys and girls are likely to hit a growth spurt, although the girls will tend to grow a little faster and be a little taller than the boys. Mentally you can expect a rapid year of development, as your kids start to gather information and formulate much better organized opinions and thoughts. Even with this development they are still at an age where they need breaks to run and play. Around this age you may start to see a more pronounced gravitation away from parents and caregivers towards that of their peers and friends.
11 Year Olds
Eleven year olds are starting to display a distinct difference between males and females. The girls tend to be closer to, if not in puberty, while the boys are usually still a year away. Despite the differences between boys and girls, everyone is likely growing like weeds (and possibly eating you out of house and home!) You’ll find kids of this age are starting to be able to reason with more adult-like logic and are thinking critically. This is an interesting time socially for children as they may begin to shift longstanding friendships to other friends that are developing at a similar pace. They are also deeply involved in peer groups and may find parents and caregivers embarrassing—don’t worry, they’ll come back around.
12 Year Olds
At 12 years old the boys are starting to catch up with the girls in terms of development. Both boys and girls are continuing to eat and sleep a great deal as their bodies develop. In the years between childhood and adolescence expect them to have characteristics of both-- bouncing back and forth between childlike irresponsibility and increasing maturity. Socially they are navigating their friendships and beginning to be curious about the opposite gender. Don’t be surprised by frequent changes in friendships around this age as they are finding where they fit socially.