Everything is changing

I had a plan for my life. However I fell in love with a guy that is so against my plan. I am ready to get married & start a family but he is not. He's saying about another 2-4 years & I am very upset by it. He knows how I feel about it but is not willing to change at all. I am the one left to change. I'm not going to leave him but I can't help but feel depressed because of this. He knows how much it means to me & that I may be unable to have kids the older I get. I just don't know what to do.