Get urself a Galaxy first and get urself familiar with airsoft before you do anything. I was a newbie back then, and bought myself a Marui MP5 which i took everything apart....of coz i ended up with lots of trials and errors which also costed me alot of $$$....So for a newbie, I suggest u go with a cheap Galaxy which you can play aroud for awhile and then can be taken apart for learning about the internal parts...if u break something, then it will only cost u less than $500...
You won't learn how to upgrade guns (and most importantly y u need to do these upgrades) before you take apart ur first AEG....
It is from my personal experience.