My aperture then crashes.
Since this happens when initially processing the images after importing, you may have a problem with an imported image or video that cannot be processed - some corrupted media.
To check this, try to launch Aperture while holding down the shift key⇧. That will defer the generation of previews. If you can launch Aperture this way, you will have to find and isolate the image or video that cannot be processed. Make sure, you have the Activity window showing to see, what tasks are running and to see the filename of any image being processed (Window > Show Activity).
Then try to force the generation of previews manually, to see what is making Aperture crash (Photo > Update Preview). You can make this screening for bad files more systematically to speed it up, since you have hundreds of recently imported media to scan: See: How to Screen an Aperture Library for Corrupted Image Files or Videos
Does it take a long time for aperture to process images? Do I need to wait until its done to look at my images?
Aperture may need quite some time to process newly imported images (raw processing, generation of previews and thumbnails, face detection), but it will doso in the background. You should be able to browse and edit your recent import while this is happening. Only it will slow down the apllication a bit. You can see the ongoing tasks in the Activity window; also, you can cancel tasks from that window.