Waiting another baby.

Is it bad I’m 20 (going to be 21 this June.) and already wanting another baby? Like bad! I had my first very young at 15 he is now 4 and also have a 15 month old. We are buying a house of our own this fall along with getting married the next year. But lately I’ve just been having baby fever for over 6 months now it’s not going away lol and would like my youngest to have a sibling close to the same age. I always have wanted a big family and my kids a very well and always taken good care of.