Misty Roberts — the former mayor of a small Louisiana town who was convicted of having carnal knowledge of a juvenile — is not happy with how her trial turned out … because she still says she did nothing wrong.

Misty’s lawyer Todd Clemons tells TMZ … Misty is “very, very disappointed” in yesterday’s verdict.

Clemons said … “At this particular point, there’s no apology that I’m gonna give on her behalf,” adding while Misty respects the jury, she plans to appeal their verdict.

As for her April sentencing … Clemons tells us, Misty maintains her innocence and they’re going to do everything in their power to convince the judge not to send her to prison.

Clemons says Misty was an excellent mayor and is an excellent mother … and they’re prepared to make a case to the judge that Misty doesn’t need to be incarcerated.

As we reported … Misty’s victim testified her son — a friend of his — saw them having drunken sex in their home during a pool party.

The 43-year-old former mayor was found guilty on two felony charges of carnal knowledge of a juvenile and indecent behavior with a juvenile. She faces up to 17 years in prison when she’s sentenced on April 17.