OP, I am different than you in that I always knew I wanted kids. However, DH was content with the older two dd's. He absolutely did not want another one. When the stick showed a very dark and surprising second line I burst into tears! After all, my dh was adamant he did not want another child. When I showed him the stick he smiled so wide I swore I never knew he had so many teeth! Through the tears I said, "I thought you didn't want another baby?" He answered, "I don't want another baby. I want THIS baby!" I guess the bottom line is - GO FOR IT! Everyone is scared when they are having kids - how can you not be? I can tell you for certain, 20 years from now you will not regret having had a baby. I can't say it's true in the reverse.
Also, I am one of those women who came off the pill and BAM! I was pregnant immediately. I am truly grateful for that fortune. I wish you the same

!