dont want hand me downs :-(

So this sounds really bad but I absolutely do not want hand me downs. I just found out I'm having a boy and my sister in law is already gathering old things she used with her son. she already gave me a huge bag of gender neutral baby clothes. I'm very thankful to have family so loving and supportive but I really dont want anything. I dont want new gifts and I dont want hand me downs. I wish to purchase everything I want/need myself. how do I tell people in a nice way that I dont want hand me downs?

*edit- the reason is mostly because 1. I want to experience buying all these things for my son especially since hes my first baby, 2. Hubby and I dont like the typical "cutesy" baby clothes that you can buy at any store like target. We prefer supporting small shops with a bohemian / pilgrim baby style. I dont want anything in loud colors, pictures or with words on it.*