what if it doesn't happen

so my wife really wants to shoot an older child and I really want the experience of pregnancy and an infant. she is 44 and I am 24 in January (please no judgment) we agreed to try one month and after freaking out about what if it doesn't happen... she reluctantly says we can try more then once. Am I being selfish, should we only try the one we agreed upon and then adopt. just need someone to tell me hey calm down all is good and here is my view. thanks in advance