Starting to think about babies

So me and my boyfriend have been together two years now and recently we have been going through a little rough patch of us bickering for days and then it leading to an argument but we are sorting it all out and are already starting to get back to or normal selfs but a 1000 times better than we ever have been. So I’m 19 and he is just about to turn 20 and we were talking earlier and now I’ve changed jobs to something more full time and permanent he mentioned how we could actually afford to have a baby now. This completely took me by shock as we have two angels already one a miscarriage and the other a decision that had to be made for my mental help and a possible baby health which is the worst decision of my life and I feel empty and so lost without my babies being here. So we were talking and he said if we get back on proper track he would have a baby with me now. (I would in a heartbeat) so I said if we are good and feel kinda ready and have talked more and are better within ourselves by the time my depo shot is due then I wouldn’t get it renewed. We both know we want to start a family young ish even before we were together we both thought it. I was just wondering if anyone has any helpful advice if I’m making a good idea of it goes ahead or anything like any fertility tips as infertility does run in my family. Sorry for the long post girls I just don’t have any friends really to talk to. TIA 😘