Pregnant with #2

Hi Ladies! My name is tessa and I'm 18. Yes, I know that's a little crazy. Before you judge though, please listen. I had my first born at 16. His name is Jayden and of course, he was not planned. I struggled a bit but we made it through and he will now be 2 in March. A couple of days ago I found out I was pregnant again but definitely did not expect this or plan this. My son's father and I had spoke about another baby but didn't think it would happen so soon. (Failed contraception.) Anyways, since that's covered now, I was wondering how it is with two little ones. How did you include your older one? What should I get him prepared for? What can I teach him? I definitely feel it'll be easier this time around because I know more of what I'm doing. Thanks in advance :) (I'm due July 13th)