I don't think it would hurt if you waited a couple of months. You could also get a breeder to hold on to a particular animal for a while before shipping. I'm in Louisiana and it's just too damn hot to get anything live shipped right now.
The boa you have picked out looks like a nice one to me. Awesome tail!
Get your tub or enclosure set up right before getting your new snake.
You'll love having a boa as a pet.