first love; puppy love
Refers to one's first romantic love, often with a nostalgic or bittersweet connotation. Can also describe the innocent, fleeting affection of childhood or adolescence (puppy love).
She married her first love.
Memories of first love stay in your heart forever.
He was my first love.
I still think about the person I first fell in love with from time to time.
She was heartbroken after her first love ended, and stayed down for a while.
Listening to this song reminds me of my first love.