Genital warts since young (no sexual contact). Could it be due to very poor hygiene or is it an STD?

Definitions matter. If your mother had genital warts at any time, you can have them show up for the first time in the first 2 years or so of life.This is because passage through a birth canal where the germ is hiding can pass it to the baby, but not show up for a while. They might recur off and on for years. Emergence after the age of 2-3 is considered evidence of direct sexual transmission.