Two *must* sizes for Birkins!

I would go for 30 for your first birkin. You'll be amazed at how much it can actually pack. Its great as an evening bag as well when its closed. My SA in france was actually the one who recommended that I get the 30 first then get a 35 later on. Good Luck!
 
Thanks ladies for your input on which size to get. I've been beating myself up for picking a 30cm. I just got it this week and am afraid to call the store to ask them if I could exchange for a 35cm. The color I got is tabac camel with gold hardware. It looks way small to me right now. I'm 5'4 and usually weigh about 110. I'm 34 weeks pregs right now so maybe everything looks small held up next to me!
 
I think 35 is great as a workhorse bag, very elegant and stylish. However, sometimes I found even 30 (TC or TOGO leather) can be a little heavy as you load it full. So when I go shopping and dining, I will be more desire to carry a 30cm.
 
wow, you've gathered lots of opinions!
Here's one more: have you held each your favorite 30 and 35 in the mirror to see how they "hang" on you? I think it's a good idea to go in with a typical outfit you'd wear your "workhorse" bag with and then hold each size in the mirror -- go with your own instinct of which size feels/looks like you. THEN you can decide on color/material after you pick the size. I actually think size is a primary factor in getting the right bag. For example, I will never forget seeing a s t u f f e d to overflowing 30 cm rouge vif birkin on a lady about your height (maybe shorter, but she was wearing heels). I couldn't help think, "why didn't she pick the size bag to fit her needs (at least today!)?"
p.s. if you love the look of black ostrich, that 35 could be your new BF :winkiss:
 
You've got a point! If you're going to be wearing skinny jeans, a 35cm would look huge. I saw a picture of Madonna carrying a 35cm in a magazine shoot with wide leg pants on and it looked great!