Don't listen to California lawyers who know nothing about Texas law. In Texas a conviction can not be changed from a felony to a misdemeanor. You can get a pardon, but barring that there is no motion to change a conviction to a lower degree of offense.
I am curious about what you pled to. The minimum sentence for a State jail felony is 180 days state jail. You should check your plea paperwork (judgment). There are certain agreements (12.44) that treat state jail felony cases like misdemeanors. Have your attorney review the judgment with you to explain.