Your family are your first peer group.
Which is odd, as there's no such thing as a peer in a family. Everyone is defined by their place in a complex, broiling power structure, and by what they do to change or maintain that place. For someone to be your peer, you must regard each other as equals.
It's almost impossible to be friends with a family member, except by both trusting each other enough to maintain a truce. You have friends at school, and in after-school associations. You have friends at work, on internet forums, and in sporting societies. At home you have folks.
Church fellowships are more like families than clubs - but that's not surprising, as authority (not belief) is the foundation stone of religion. Which is why you can be a member of a church without even knowing it's doctrines, and if you're a dominant member, you can make the doctrines.
Political parties also are, to slightly misquote Marx, "Bands of hostile brothers". In my experience, university departments are the same, with enough nepotism, sycophancy, jealousy and back-stabbing to match any royal court.
If you want to know whether your association is a peer group or a family, look at who gets into sexual relationships with who, then why and how the relationships end.
So, if and when you grow up and leave your progenitors and siblings, you have a choice. Find a substitute family, or find something better than a family.