It's still a bit puny isn't it. There are two things to do to change this.

First, go back to the terrain editor.

Using the 'raise/lower' button in the editing tools(1) the terrain can be raised to the highest level Bryce can use. However, you don't want it to give you flat topped peaks so it's important to stop when you reach the top. If you do go to far you can either move your cursor in the 'lower' direction or else you can use ctrl+Z.

If you like bright colours and find it hard to know when you're reaching the upper limit of the terrain height there is the option of colouring your terrain map with a gradient (2). There are lots of choices, pick one that has a lot of range of colour at the top end and you'll see when it reaches the upper limit more easily. (3)

Leaving the terrain editor and rendering now will show that you have a slightly more massive mountain. It's got a lot of growing up to do still.