What's wrong with my transmission?

Every now and then my 1999 Saturn SL1's automatic transmission seems to have problems. It lags in shifting and won't shift into 1st gear. I'll come to a stop and then when I start to go I go really slow because it refuses to go to first gear unless I push the pedal to the floor then eventually it jumps into first but by then I'm already going too fast for first and my rpms get all crazy. After driving it for a while it will quit doing this, but its not because the transmission is cold because sometimes it will do it when i turn off my car for a few minutes and then turn it back on when everything is still hot. Is one of the inner-transmissions-gear-clutches slipping? whats going on? im good on fluid...
What's wrong with my transmission?
Saturns have known problems with 1st gear not going in everytime. We own one. Your best bet is to go to a shop to verify it. Rebuilt one is best way to go with warranty.