Its excessively tall, in my opinion. Of course, if you like it, it won’t be excessively tall. It might also be challenging to make judgments from a photograph because you can’t tell how much is buried. That one is still too tall.
Too much water, not enough light, or both are signs of excessive height. Lithops don’t require a lot of water. It’s possible that your soil retains too much water or that you irrigate your lawn too frequently. Obviously, a big (and tall!) plant like this one shouldn’t be watered at all until the old leaves have fallen off.