Is there a big difference between the 30 and 35 birkin?

well bbc it kind of does happen to me im not petit more on the thin talish and i do consider the 30cm as a dress up evening bag as oposed to the 35cm in leather that i all ways wear for day and my one 35cm croc i never wear i just think its the wrong size 30cm in exotic for evening 35cm in leather for day bag sometimes i feel im the one thats off but then thats just me i guess !!!!! bit crazy