Shifts hard into 1st

My car shifts hard into first gear whenever I come to a complete stop. This even happens sometimes when I slow down to a roll and then press down on the accelerator. It just seems to rev up a little, then slams hard into gear.

Also, when shifting from 1st to 2nd, the RMP's seem to shoot up before it actually engages into 2nd gear. Its like the trans temporarily disengages, then the RPMS go up, then the trans grabs 2nd gear. This usually happens when I am accelerating harder than usual.

My first instinct was to get a trans fluid flush. I have been advised not to do this by a coworker (who doesn't happen to be a mechanic). But honestly, I am somewhat hesitant to flush the trans fluid etc because he told me that it could lead to more problems. Something about the little shards of metal in there will be removed and the trans will not be used to it. Something like that. Anyways, would a trans flush be a good start to fix the problem? OR is this a more serious problem? Torque converter perhaps? You guys have helped me out in the past. And I appreciate your response.

Thank you.
Rich