aww....no way are they selfish. You mostly find other people are nagging you to have them (I do it to ppl, lol) rather than you making people come and buy you presents!!!!!!! It's more about celebrating a new baby coming into the world, not being greedy. When I have one I think I'd write on the invitation that presents aren't neccessary that I just want to have a nice day with the girls!!
Do what you want, if you want one, have one!! It's a great time to celebrate!!