Yes you can drive it at idle rpm, but it will be going pretty slow no matter how far you push the pedal down. The forward speed is a combination of engine RPM and which range you are in and how far you push the pedal down.
I believe on the
BX25 you have to purchase the arms for the 3 pt hitch in a kit. You would need them if you take the BH off and put something else such as a rear blade on it. So check on the cost of that. As another mentioned, to remove snow, you will want something in addition to the FEL. You could put a snowblower on the front or a front blade. Where I am we don't get a huge amount of snow, so I use a rear blade and the FEL.
If you are sure you will want/need a BH, buy it now as a
BX25. It is a good buy and the other BX's really aren't built to have one added. When I bought the
B2920, it was the same price as the the
BX24, each with a FEL and MMM, but I did not get the BH. At that time I decided I needed a bit bigger tractor and adding the BH to mine isn't a problem except for the money part.
I don't know about driving as a 15 year old. It has been a long time since I was one. But I would think they would let you. Have fun. I am off to mow on our other property. The tractor is already on the trailer.