Your next step is to determine whether the boot is too large or small. If you are still
growing, or your weight changes (or your fluid content alters due to
natural body cycles), you may find your feet change with time, so this may
need to be redone periodically.
Boots are generally smaller as you move higher up. To make more space, remove the insole completely, or use a thinner insole. To make less space, use a thicker insole, or add in another.
Make a new insole by tracing the old one on top of a piece of leather or felt, then cutting to the same shape. This helps prevent the insole from sliding around.
Glue together multiple thicknesses if required.
Keep the old insole so you can repeat this step when needed.
Some people skate without socks (though that breaks down the leather a little faster), to gain better control, or to make more space. In any event, it is a bad idea to use thick socks, because they are too squishy, leading to a loss of control.
You can make the insole wider than the original in places. The insole will wrap around to the sides of your feet, reduce the effective width.