Personally, I'd consider a small backpack.

I mean, let's face, we're already wearing a garment that many consider to be a "skirt," so personally, I'd avoid carrying stuff in something that looks like a "purse" such as a messenger bag. But, maybe that's just me...

Lucky you! Looks like you've got yourself a fine little companion there. I'm sure you two are going to have a lot of fun together!

.