Extremely Insecure about sex 16M

hey! i’m a teen and i’ve gotten somewhat into sex (never had intercourse but i’ve had gotten head plenty of times) and as of late i’ve been becoming extremely insecure about my body, to the point that i don’t want to show it off to a girl i might be interested in, and it’s not that i’m scared about size or anything (i’m fairly large around 8 inches and average girth) but the thought of showing my chubby disproportionate body with multiple stretch marks scares the hell out of me, is there anybody here who as had this feeling and how do i get over it, thank you for your time.