IPhone 5 printing off photos 4x6?

I want to print off developed pictures from my iPhone at a local photo center (Walmart, Office Depot, etc.) and I'm wondering if the pictures will be cropped because of the size. I want the 4x6 size pictures and I don't know if size will effect it or not.

Well, look at one of the photos off your phone, and check out the pixel dimensions.

If those dimensions are in a 4x6 aspect ratio (for example 1200 x 1800), then you'll be good to go.
If the aspect ratio is different, then you'll need to first crop the photo, or put it onto a bigger background so it will print with a white edge (which you can then later on cut off).