Your set up seems adequate to me with the security upgrades. My first snake was an adult bp and I kept him in a very similar set up for about a year before he began pushing to get out. He managed to escape a couple times before I found spring clips that were secure enough. Unfortunately, that didn't stop him from pushing and he started to injure himself. I solved that issue by building him a larger enclosure.
So, I suggest you start planning for a larger enclosure. Your bp is a baby so you've got time. You'll know your snake has been pushing when you see swelling, usually on the lips or the top if the head. Even if your snake doesn't start pushing, a larger enclosure is worthwhile. With more space you can provide a healthier and much more enriching environment.
But that's down the road. What you have is perfectly adequate for now. Take this time to get to know her. The better you understand her, the better job you'll do when the time comes to upgrade.
P.S. What are you regulating the heat mat and ceramic heat emitter with?