I remember watching a movie where a school boy (may be around 13 year old) fall in love with a girl or similar age. Boy tries to charm her in many ways. In the middle of story they also became good friends, they are in some kind of karate classes too. Girl is good in karate and teaches the boy too. I think there is some problem in girls family too.
In the end of movie boy proposed the girl but girl rejected him by saying that they are not in the age for love and movie ended.Boys last word are like saying that he can't forget his first love in his whole life.
It's color Hollywood film may be of 90s or 00s but i am not sure.