I'm interested in buying some riding boots. The problem is I have never bought any prior to this or even worn any "riding gear" for that matter (always wore my work boots and beat up clothes to ride) and I'm wondering if the sizes are determined just like regular tennis shoes are? I'm a size 12 in a shoe so I guess I'd need a size 12 riding boot then right? Sorry for the dumb question but I plan on buying from E-bay because I don't want to spend a ton at the stealership and I don't have the time to go out and shop for them elsewhere. I just don't want to get the wrong size.....