Render Frame Rates

Relax, will you ?  EVERYBODY goes through this with AE!  You just need to learn how AE previews.

Lesson One:  don't hit play.  Hit zero on the numeric keypad, and give AE time to create a RAM Preview.  This is NOT a video editing application, you know.  AE has to render all the video.  That's how it works. 

Too impatient for that?  Drop AE and start using Premiere Pro.

Lesson Two: don't expect AE to play back in full frame rate under all circumstances.  You'll be greatly disappointed.  Instead, drop comp resolution to half just to check the motion -- PEOPLE DO IT ALL THE TIME!

Lesson Three: get to know the Views And Previews section of AE Help for more helpful strategies in previewing.

And keep them fingers off the space Bar!