As an additional suggestion, because you have now dedicated the AE/AF lock button to focus, you lose AE lock. There should be another menu option to assign AE lock to the shutter half-press. This will now enable you to separate all the functions nicely. You can choose your focus point and re-compose, and you have a choice of where you take your exposure reading without using another button. Most of the time you can simply ignore it and let the matrix meter do its thing, but sometimes you want it on the same spot you focused on, and sometimes on a spot different from both. All those possibilities now exist independently.
As other sources will probably note, if you are using back button focus, it's advisable to set your AF to AFC (continuous). BBF gives you the best combination of focus modes. If you hold the button down, you get AFC, and if you let go of the button, it basically duplicates the focus-recompose convenience of AFS.
I got used to BBF on a D3200, in part because it is the only way to get shutter priority in any focus mode on that camera. That made following action, such as birds in flight, a problem because if focus deviated slightly, the shutter would not fire. even if the subject was still in focus. Shutter priority is useful here, and BBF was, as I say, the only way to get it on a D3200. I believe the d5x00 gives you a priority choice for AFC. . Shutter priority is usually recommended anyway, so that you can keep shooting with the back button down, but in any case, when you let go of the button, it's always shutter priority.
You should probably also experiment a little with your camera to make sure you know all the quirks. The D3200 had a quirk in that BBF was disabled entirely when using the remote, and also in Live View AFF, though it works in AFS.
It took me a little while to get used to BBF, and I missed a few shots forgetting to focus, but I'm now so used to it that I will push that button on other people's cameras and wonder why it doesn't focus. Stick with it, and I think you'll be glad.
One final note: some older references may mention that AV only works with the shutter button. In newer cameras, of which yours is one, this is no longer the case, AV engages with both back and shutter buttons.