The mother of the 3-year-old girl dressed as a prostitute on "Toddlers and Tiaras" tells TMZ, she's a good mom -- and insists "no harm was done to my child" by dressing her as a hooker.

Wendy Dickey tells us, her kid had no idea what she was dressed as anyway -- and the costume was "less revealing than gymnastics wear and swimsuits."

According to Wendy, the hooker outfit (below left) -- based on Julia Roberts' character from "Pretty Woman" -- "is a lot less harmful."

Wendy says she dressed her daughter as the "classy" Julia Roberts from the end of the movie as well (below right) -- but TLC edited that part out.

Wendy says, "I'm raising my child just as well as any mother does ... I take my kid to church every week ... at least I'm not forcing them into sports and getting my child injured like some parents."