How did you ladies decide that you wanted to try and conceive again? My fiance and I are getting…

How did you ladies decide that you wanted to try and conceive again? My fiance and I are getting married in August and we plan to start trying to conceive in early 2020. We've been together for 3 years. He's been a father to my daughter since she was around nine months. He's a great provider. Makes six figures and we live a very comfortable life; but I cannot shake the feeling that I'm not ready for another baby. It's weird I have baby fever but the closer I get to actually putting our plans into action the more I'm afraid that things will not go to plan. My daughter wants a sibling. My fiance said he would be ok with having a baby or just having our daughter. I'll be able to stay at home with the new baby instead of having to work and go to school like I did with my daughter but I don't know if that's what I really want even though it's what I've always hoped for. We have a stable life it's not like I just met this man 3 months ago and wanna start trying. We have plans for our life together I just don't know if expanding our family should still be in our plans.