I don't have diapers!

I want to get diapers! I know I want them from Amazon, now know my size, and what I want to buy and I have money to get them. But the last problem standing is... How do I get them past my mother and grandmother. I am 18 but I still live on their house and because I am 18 I have a reason to buy this myself. But they can't know I want to have a lifestyle like this yet until way later. Everyone how can I get them past everyone in my house without them knowing they are diapers? What am I going to say it is that is delivered? I can lie I absolutely hate lying and will not do that but if I bought it with something else would it help?

Also... Will the diapers come in an Amazon box if their from Amazon?

I don't have diapers!