First of all, you should really consider updating AE. If you don't want to get this year's version (CC 2015.3 - the latest update that came out today is version is 13.8.1), you should at least get the latest update to your version (CC 2015 - latest is version 13.7.1 on Windows or 13.7.2 on Mac). There were a lot of bugs fixed between 13.6.0 and 13.7.x (and lots more in 13.8.1)!
Secondly, that's just usage while it's loading. I'll bet, if you start caching a preview, you'll see your RAM usage start shooting up.
Give After Effects more to do. It uses as much RAM as it needs to.