16w and have nothing for my baby

Should I start buying ? My mother in law mentioned it’s best to wait after I mentioned a stroller ...but after paying for a party (baby shower) I’m not sure how much spending money aside from bills and rent we will have to spend for things we need.... like a far seat , stroller , counters , ext I don’t even have clothes I don’t have anything at all I know I’m only 4 months but I won’t be able to afford a shopping spree a couple months before the baby is born. Any tips ? I’m a first time mom not sure what I’m doing ... what should I start buying? I wanted to get the expensive things out of the way I already have a crib ... but should I really wait for a stroller and car seat mind you I have not one thing for the baby yet ZILCHHH NONE!!