I'd have a chat right away. I'm 35 and also waited to have kids, now I am facing infertility. Just because some 40 year olds get pregnant does not make it common or easy. Get ovarian reserve testing done ASAP. Then you'll know what your situation is.
First you do need to communicate with him and find out if he wants a child and where your relationship is going. And let him know you do want a child. If you are not on the same page then there you go.
Second there are lots of men who like women with children. You don't have to give up on the championship. Just maybe you too are not meant to be if you are not on the same page and wanting the same things.
Third, you can go through freezing your eggs so when you are ready with him or some other gentleman or a donar you won't miss your opurtunity
Have you spoken to your boyfriend? This is a personal decision you have to make. Choosing to have a child with a donor will probably end your relationship. How does he feel about this? Your 38, you probably have another year or 2 before you have to worry, but you may need to have the biological clock convo with the boyfriend and at least gauge how he feels about it. I know you're not supposed to pressure a man, but be clear that you plan on having someone else's child if he doesn't want to be the father.