26 Year Old, 3 kids, petite frame 355cc Sientra HP under muscle.

I had my consultation last Wednesday & I just scheduled my BA date for 3/18/15. My pre op apt is 3/5 and I am freaking out a bit, anxious and excited. I'm 5'1 and about 95lbs. The PS said I'm very narrow and 400cc will be the absolute most he will be able to fit. Originally all I wanted was 250cc (just want to be normal) but hey since I'm paying a good amount for them why not go a little bigger. I'm back and forth with sizes between 300cc or 350cc. High profile, Sientra, silicone, under the muscle. My husband has been very supportive and though he thinks I'm "perfect" understands and supports my decision and knows that I'm doing this for me, to have more confidence in my appearance. In the end it will benefit him too lol. I am currently 32A. I am a mom of 3, will only have help for 4 days so Im a little scared about that but very excited to finally have boobies that I've been dreaming about since junior high!! ;). I've always been an A cup at least before children they were perky. I absolutely loved how my boobs looked when I was pregnant but after that and breast feeding they now are completely deflated. This site has been very helpful and I hope that I can help someone through my experience.

So last night I had a dream I got my boobies! Lol! It was a great dream.. ;) I'm a month away and I'm getting really impatient. I've been thinking of doing this for so long and now that I have the date it's the only thing I can think about.
I really want to go and buy some things that I will need for post op, if any of you can recommend anything especially any creams I can put before and after that help with stretch marks I would appreciate it. I got a lot from my pregnancies and hoping I can use something that won't make them worse..
Also I want to get some sports bras that zip up. But how do you know what size? Just kind of guess? I won't be able to get them after so I want to be prepared! --Anything that you can recommend I will need would be great! TIA

So I got a phone call yesterday from the PS office asking if I want to change my date to 3/6 which is way closer than 3/18. In reality I would have loved to. Especially bc all i can think about lately are boobs. Lol Literally have been looking at boobs every day all day lol. Unfortunately I couldn't move my date bc I won't have any help that week with he kiddos so I had to keep the 18th. Wahhh.
But why is it that the second she asked me that i immediately got anxiety?? Anyone else feel the same way, I literally feel my heart palpitating when I think about it! Lol. Don't get me wrong I'm very excited and can't wait, of corse nervouse too but wondering if I'm that nervouse on the actual day will they give me something to calm me down?? I feel like I will be sick with the combination of nervousness and then not eating for however long.. I just have all these mixed emotions I can't wait until the day so I can stop over thinking everything! Ahh rant over..