Buying stuff for baby

My husband's family always seem to have an opinion about stuff I buy for our baby. I've been told that I'm buying too much for the baby and that I shouldn't buy so much before the baby shower. Why not?? I'm 32 years old, pregnant with my first baby that I've patiently waited to have for a long time! I'm excited! It's not even like we've bought that much! There is still so much to buy, and there are still a lot of more expensive items on my registry. The main person who comments about it doesn't make a lot of money, and I know she won't be able to afford to buy us much anyway!  Did you buy a lot of baby stuff on your own? Or did you wait until after the baby shower?