what is the diffence between lamb and mutton? What's the diffence between lamb and mutton? Which word should I use when I got a dish cooked by goat ?

A New Challenge in Future Twillight cames up, Yang,one of my firends and i roamed in the park trail after the dinner as usual for breathed fresh air.We are living close to each other,and our parents are firends too.Yang told me "I love you ,I want to be your life partner"suddenly, then told me one of the reason is I could listen all of his tiny troubles carefully and finger out how to solved them. It made me shock at that moment,because we have the same sex as male. I didn't know how to reply him in 3 or 4 secs.I didn't want to hurt him ,tried to find some suitable words to refuse him and told him I like girls only. lol Finally I decided to tell him diretcly. It maybe the best way to deal with it.when I told him i love girls only He turned the topic to another area quickly,and didn't show the emotion like painful . It made me could breathe again. Hope my reply is okay.I like him as my firend.He is a kind, smart man.we can exchange our opinions in many areas like charcoal drawing, newage music, documentary, books, politcs.I don't want to lose him, How to deal with the relationship between us correctly is a a new challenge in future.lol