My daughter really wants to be a big sister but my husband and I don't think we want any more kids.

We have a super sweet, empathetic, polite little 2.5 year old. Many times I have told her she has to be at least 3 for mama and daddy to talk about maybe having a baby. Many of her friends have siblings and very often she says "my be GOOD big sister". Every time she sees a baby she gets all gushy and for the rest of the day it's big sister this and baby that. We have explained the extent of sharing she would have to do and her response is "my good sharer". We don't know what to do. We haven't been able to put any savings away in a very long time. My husband is in the beginning stages of a great career. Our biggest goal is to purchase a house. Right now we live in a small two bedroom apartment. We have discussed how we would make it work but I am so torn. Of course I would like to have another sweet wonderful child but she has been SO easy I don't want to change anything. I used to have a dog. He was an Australian Shepard. The best, easily trained, super chill and absolutely wonderful. When he was 6 or 7 we adopted a stray so our first would have a playmate. He has terrible. Bad habits and dominated our baby boy. We weren't able to do many of the things our first dog loved, he didnt really like to play with him after a while. He didn't get enough attention because he was so easy and the new dog needed so much. When he passed away I felt so much regret for taking all this away from him. I feel there is a lesson there that I am supposed to learn. Be happy with what you have. My daughter isn't a dog but there is something there. But..... "My be good big sister!" Cue tears via /r/Parenting http://ift.tt/2DCLLJW