Trying to figure out what this 70s movie is that I haven't seen in years...

Years ago I saw this movie on TV. I have no idea what the name of it is. All I remember is, I think it was set in New York City, about two high school students, a curly dark haired boy with glasses and a blonde girl. The boy I think played an instrument of some kind. I also remember a scene where they go out together to a restaurant and the girl asks something like "What are you?", he replies "I'm a sophomore." Then she says, no, I mean, what's your nationality? He replies "Oh, I'm Jewish"...

It's such a vague memory because I haven't seen it in many years.

Can anyone identify what it could be?

Thanks.