Am i being selfish??!!

Im 24 years old. i have a boyfriend and he makes me the happiest girl ever. BUT theres some things HE WANTS that i dont. and things i want that he doesnt want in a relationship in the future. The thing he wants that i dont want to to have children. I wasnt in a big family. And was practically the only older child growing up by myself so i learned to deal with things on my own. He wants children because hes 25 and has a BIG family than mine. I just dont want children. i dont picture myself having kids. 😧 Another thing he wants that i dont want is a big wedding. He likes weddings and to attend wedding BUT i dont , i was in alot of weddings when i was a kid , the flower girl but im very shy and insecure with myself so i will not be having a big wedding, i just want to get married through court. Anyways with that being said , am i being rude and selfish? Or am i just being me and different ? i dont want what other women have , children. Do you think he will leave me for this ? please answer and no rude opinions. 😪🙏