Here are some averages:
From 9-11 years, your child might start to show more independence from your family and more interest in friends.
From 10-14 years, your child might want to spend more time in mixed gender groups, which might eventually end up in a romantic relationship.
From 15-19 years, romantic relationships can become central to social life. Friendships might become deeper and more stable.
Many teenagers spend a lot of time thinking and talking about being in a relationship. In these years, teenage relationships might last only a few weeks or months. It’s also normal for children to have no interest in romantic relationships until their late teens. Some choose to focus on schoolwork, sport or other interests.
For some young people, sexual development during adolescence will include same-sex attraction and experiences.
For 3-10% of young people, the start of puberty will mean realising they’re attracted to people of the same sex. A larger number of young people might develop bisexual attraction.