Wanting to get prego

I want to have a baby so bad. Badly enough that there are days that I'm so upset about it and I can't think of anything else. My boyfriend says that we can't afford a baby right now and every time I try to explain to him how I feel and how upset I am about it the only thing he can say is it will happen one day and it's ok. I'm 27 and I feel my time is running out. What would you all do in my situation?