Baby Shower Registery opinions

 This is my first pregnancy. I registered at Babies R Us and Buy Buy baby. I took my time to each section scanning on things need and will need later in the baby first year, example sipping cup, swaddled, blankets, safety locks around the house for the baby becomes mobile etc.
 My mom for some reason is having an issue about me putting on a registery items that are not new born or under 3 months more specific. She say baby showers were people buying newborn gifts, not for older babies like 6 months to 12 months. 
How I see it, I be happy with any gifts beyond newborn that can help in the first year at different stages of the first year like sippy cups, bowel, utensils, baby proof items etc. I personally don't have an issue with it because babies grow. I'm humble for any gift really even just baby  power...
 I'm have two baby showers due to both side of families & friends. Which they are a 10 hrs drive  from each other, in order accommodate both side. This child will be beyond bless & spoiled on both ends.
 I guess my question what is right?  In regards, to my opinion or moms, or really the traditional way of doing things. Should  my  Registery focus on items under age 3 months but I feel I need other things later in the year.
 I even told my mom I forgot to add baby hangers to my list. For  hanging baby clothes and she got bent out of shape with that.
So what is right way now days???