lumina transmission

wont shift down to first or second gear reverse works fine it feels like it is taking of in third gear and it just happened all at once

Welcome to AF and the year is???

97 lumina

Trans could be in limp mode as you descibe, this can be caused by an internal electrical issue, power feed to trans or even a mechanical internal problelm, no quick answer here. A scan with a trans function scanner may reveal a code or a possible solenoid problem.

Loss of inputs from the range sensor (formerly called a "neutral safety switch") can cause those symptoms, and force a "limp mode" as the Wedge-Driver explained. You could meter the signal inputs at the PCM, or simply scan it as advised.

Of course, there are numerous other possibilities, many of which might be revealed in a PCM scan.