First time ever drawing a portrait. (I've typically drawn super heroes comic book style) Shading with pencils is new to me

Somewhat experienced beginner here, I've been drawing super heroes on and off for about 3-4 years now with most of the stuff I've learned coming from YouTube and no formal art training. (I wanted to take this course so I could be sure to learn and sharpen all my fundamentals) This is my first life drawing (is a pear considered a life drawing?) and I'm don't think I'm particularly good with shading with pencils. I used an HB, 2B, 4B, and 6B pencil