Unless you want to look like you're a hipster who thrifted the shirt for $2 and refuse to use an iron because of its electricity consumption.
Oh, and buy a can of Sizing, NOT Starch.
Is this what you were talking about?
Yes, this makes sense. Most Internet sellers have a point of no return, after which you cannot cancel, or edit an order. So when the suit arrives, you will have to return it by mail or to a store, both of which are fairly easy.
When I order a suit online from BB, it usually takes me at least another 7 days after I have the item in hand to get it ready to wear, since my tailor takes at least 7 days turn around time to finish sleeves, etc. So if I were in your position, if I ordered a suit on Christmas day, I would not expect to be wearing the suit until the second week of January.