Doing your own delta time works, but there is another more common approach which I figured is worth mentioning. The game logic runs in a loop that "ticks" 20 frames per second. The render refresh rate can vary depending on your monitor, settings and power of your GPU.
So whenever you're doing animations in Minecraft you should set the positions and angles based on the game ticks, not the refresh rate. So you would really increment the position every tick rather than every event (which fires at the refresh rate). However, doing that has the side effect that it will look a bit jerky because it will only update position 20 times per second which is a bit less than needed for perception of smooth motion (traditional movie film used 24 fps). So to smooth it out, there is the concept of "partial ticks" that are passed to the rendering methods (and events).
So an alternative, arguably more common, way to do animations is to update the position using the ticks plus a bit of adjustment using the partial tick. For example, the game overlay event has a getPartialTicks() method to help with this.
Just thought you'd be interested. Point is that partial ticks are used to communicate difference between refresh rate and tick rate and are commonly used to control animation speed.