请问怎样用英文表达“初恋”这一词语呢？

Puppy Love/First Love
后者用得更多吧
例：
我侄子初恋时和他的小女友手挽臂而行。
My nephew in puppy love went out with his date arm in arm.

海蒂是我的初恋，也是我第一个亲吻的姑娘。
Heidi was my first girlfriend and the first girl I ever kissed.

first love

first love

first love