my 97 ssei w/ 138k miles;
when i take the car outta park and put it into drive or reverse i have to wait for a little shake to start moving.... if i dont the car revs up then jerks and gets into gear

Tough to say from what you posted if the trans is dying or not. Once it engages does it seem good and solid or is there more jerking and shuddering or slipping?

Is the fluid at the correct level, clean, non-burnt smelling?

The first thing I would do is check the fluid level. When was the last time the fluid and filter was changed? A plugged filter can do this.

https://www.gmforum.com/t278813/

the fluid is leveld but it was empty when i got it and isk for how long.... do u recomend that i change the filter and fluid or a pro
and it never slips it only jerks if i take off "fast"

If it'* jerking when you take off fast that sounds like a mount. Check all the motor and trans mounts.

its not a jerking jus like one jerk when i take off but is changing the filter a difficult task

More that one jerk wouldn't be a mount. A single hit could mean that the engine lifts and hits the maximum or next mount.

Jerking is usually more of a studdering in the trans and worse to fix than a mount.

As for changing the filter, there is a how to in the techinfo section. Not a bad job, but after the 20 bolts, your arms will probably be tired.