A.W.
Wow, I only read a couple responses and was shocked at what was said to you. I don't think it's a matter of being selfish, but there is the matter of manners and priorities.
You do have from now until November to spend a little money here and there to get the items you need (when my son was born- he came into the world and I already had a floor to ceiling tack of diapers in varying sizes), buying a little at a time makes it easier. You may also have a skill you can put to use making extra money to buy things for the new baby- do you sew? do other crafts? photography? etc....don't forget to shop clearance racks for baby clothes right now- winter newborn stuff will be at about 70% off....do that for each season (shop at the end of the season for next years season)till you have kiddo then you can keep the pattern going for years!
as for the shower itself....etiquette dictates that a shower is thrown FOR you, so if someone decides (on their own) that they would like to throw you a shower, then that's wonderful, but showers should never be sought or expected whether they be baby showers or bridal showers.....