Caley, I would suggest that you buy the 2 other Speedy 30's to add to your collection and just keep the 25's as well. I know it seems like an overabundance or even redundance (did I just say that??? lol), but I rather like having the idea that you have size variety for any and all occasions! This is coming from someone who can't part with any LV at the moment so go, go, go for two more! LOL Then share pics!
It's interesting because I know that I'm taller than you but sometimes when I see the 25 I think, "Oh, how cute" but realistically, I don't think I could carry something that small especially as it's handheld. I think you probably look really chic with a bigger bag, but definitely try out the 25 as a test run. You have so many other gorgeous bags and so many LEs to get this season though - are you planning to get the classics soon or wait?
25 is TOO SMALL. I only still have it because Cerises didn't come in the bigger sizes