Am I being controlling?

My sis is throwing me a baby shower. Thing is, she wants it to be a surprise because she wants it to be "special". However I don't need it to be a surprise to be special. I actually would prefer to have some input on some things cuz I saw some cute ideas on Pinterest. When she originally offered to do my shower she said I coudknt "micro manage" it and couldn't ask any questions or anything. Well, now I wish I hadn't agreed to that, 1 being I don't see me sharing ideas as micro managing and 2 I need this shower to be as functional and practical as possible since me and the hubby don't have tons of money. To top it off, my mom shared with me the cupcake flavors and turns out my hubby doesn't even like either flavor. When I asked to have one changed so he could actually enjoy the dessert at the party my sis got mad and said "no, there is a theme going on " and said I ( the mom to be) am not planning the shower so I don't get to choose. With prego hormones running wild, am I in the right to be able to share my input on my own baby shower or am I really being controlling?