Welcome to the forum!
My kit took approximately one month to arrive but it's going to vary based on the availability at SeemeCNC.com
My suggestion is to go to seemecnc.com and leave them a message and ask them the expected shipping date
or a tracking number if it has been shipped. They are a bunch of great guys and they won't mind your question.
Make sure you go to http://forum.seemecnc.com/viewtopic.php?f=39&t=987 and download the second revision
of the build guide. Any questions you have about the build you can submit through this forum or SeemeCNC.com
The forum has a large number of users with diverse backgrounds and someone will answer your questions.
Once you have the guide, read up on the things you need that AREN'T supplied with it - RTV sealant, wire crimper/stripper (Vise Grip makes a really good one), soldering iron, kapton tape, heat shrink tubing (and a heat gun), wire nuts or crimps, etc. will be necessary. May as well get that stuff lined up ahead of time, so you don't realize you need something you don't have five minutes after you unbox the kit.
You might also want to take a look at the SeeMeCNC store to see if there are any parts you might want. I got my kit a while back and I don't know what they ship it with these days, but I wound up getting an Onyx heated platform, pen holder (this is really a must-have as you can use it to mount a depth gauge - get one of those too, they're cheap), EZ-struder, and some extra Bowden tube. I also got the LCD adapter board, but I think new kits ship with that already. (Used to be you had to build a cable harness.)
I don't know if the Rostock is shipping with a glass build plate these days, but you're gonna want one of those too. I had a local glass cutter fashion a 280mm plate out of tempered glass. (You have to tell them it's for high temperatures over long periods so they don't give you something that will crack.) It cost me about $30 US. If I had it to do over, I'd get it a little wider so it came out all the way to the edge of the platform. The Onyx board will warp when heated, but putting oven glass over it will give you a perfectly flat platform that will never scratch. I build with PLA and getting the parts off the glass is way easier than dealing with blue masking tape. It's said to be good for ABS as well but I haven't tried yet.
I used "butterbeans" because Amazon could ship them to me quickest. They are alright but I think inline crimps are better. I tried using them for the hotend resistors, but the plastic cases eventually cracked and fell off.