My son wants a baby sister

I have been trying to concieve baby #2 for about 14 months now....but for the past 2 or 3 months now my 4 year old son who will be 5 in a couple weeks has been asking for a baby sister.... what makes me smile and breaks my heart at the same time is that he would find random objects (((like a pigeons feather))) and he would say mom im going to save this for my baby sister 😭😭😭...i know he would be a great big brother because he is already saying that he would help feed and bathe the baby an he wants her in his room so that when she wakes up he can be there for her.... I really want to give my son the baby sister (or baby brother) that he is asking for but everytime AF shows her ugly face i get sad.....but i can already see his reaction if me an his dad were to tell him that he will be getting his baby sister or baby brother soon.