After Effects preview keep playing back at a certain time when i dont want it to

As Rick already pointed outr, it would be a good idea to read the online help. You have completely wrong expectations and a lack of understanding what AE is and how it works. What you experience is called a RAM preview/ cached preview because clearly something in your composition or your computer's specs prevent a realtime preview and within the AE world this is perfectly normal.

After Effects User Guide

Mylenium

After Effects is NOT a video editing application, it is an animation, motion graphics, and compositing application designed to create shots, not movies, that cannot be made in an NLE like Premiere Pro. After Effects decodes every pixel on every frame, processes each pixel with effects and transformations, assembles a new frame and moves on to the next frame. The average composition a visual effects professional creates is one shot. Most shots in most movies are less than 7 seconds, so most AE comps are 7 seconds or less. 

Because of how After Effects works and how it was designed, you should not expect long ram previews. It is the same for 3D and all other effects and compositing apps I know. You work on shots, then use an NLE to make the movie.

You can skip frames in the Preview Panel. You can extend the preview time by lowering the Composition resolution to half or less. You are not likely to ever get a Ram preview that lasts over six minutes. 

An efficient After Effects workflow involves pre-editing your movie in Premiere Pro or at least picking the in and out points for each shot, creating a composition for that shot, applying your effects and animations, then rendering that shot to a production-based, visually lossless format (not an MP4) and doing the final editing, sound mix, and color correction in an NLE like Premiere Pro. 

Spend some time in the Learn Workspace and look at the User Guide to figure out how to use After Effects efficiently.