To conceive or not to conceive any advice???

My husband and I have been talking about having a second child for awhile now, we both want to right now but I'm in school and while he says we should just go for it, I'm nervous. Our daughter is three and just don't want a super big age difference in our kids but I haven't lost all the weight from her either. But every time I see a pregnant woman or a baby I get the urge... any advice?