Yes, I think that's definitely an issue at first; the numbers can seem a bit overbearing for the task. To get the focus off the numbers is key. The numbers only matter to me when I check the word count of a sentence I've already written.
The only other time I focus on the numbers is when I am done and I check the final count for the whole story to make sure it's right.
I think the reply from @letalis-laetitia could help greatly with getting you used to using the numbers but not letting them affect your work, and aid you in estimating the sentence lengths at the same time.