I want a baby.. Am I wrong?

So my boyfriend and I have dated on and off since 2011. Last May (while we were only "talking") I got pregnant (not intentionally), only to miscarry July 3. After that we kind of just went our separate ways until February this yr. We started talking again, and by July we decided to become "official". Things have been beyond amazing this time around. We don't fight, very rarely disagree, spend almost every min of our free time together, things couldn't be better. We've talking about the miscarriage, and babies and we both agree that one day we'd actually try to get pregnant.. I kind of feel selfish, but I'm ready now. I'm 25, he's 31, we both have good jobs and the means to financially support ourselves and a baby. He also has another child (8) and says he doesn't want to rush things just yet, because he doesn't want her upset. I totally understand where he's coming from, and respect his decision .. I truly do love him and am willing to wait till EVERYONE is ready. It's just at times, I kinda feel like "ok, his little girl is 8, she'd totally understand and would love the big sis status." Then I feel soo selfish for thinking that.  Am I wrong?