how long did you wait?

My husband and i welcomed our princess into the world two weeks ago which lead us to the conversation of what kind of birth control should I get on which lead to us talking about how many years we want between our kids. I said that after she turns a year old I want to start trying for another one. It took us a long time to get pregnant with her and we had some complications along the way. Plus I had a C section and I've heard the older you are the harder it is to recoup from them and I mean I'm not getting old by any means I'm only 20 but my husband wants to wait until she's four to start trying again. We agreed on three kids and I'm just thinking that if we have four years between each of our kids depending on how long it takes us to conceive I could be in my thirties by the time we are done having kids and while there is absolutely nothing wrong with that I kind of wanted to be done having kids by the time I was 28. I know still young but I want to have my kids young. How long did you guys wait between kids?