Your best bet is to run this gun hard like a champ until it turns to dust. Leave it stock.
Most of the experienced folks on this forum (like the answer above) will probably tell you the same thing. You could
upgrade this gun but you would be wasting your money because you might not get much out of it and might find it hard to make your upgrades really work properly.
To be specific, you might have to spend a sizeable chunk of what you've already spent to do any serious upgrade work on it, driving up the price of your cansoft gun to the price of a more serious, full-metal midrange AEG.
Instead, I suggest you run this gun nice and hard, saving your money over the months, get age-verified, and then buy a full-metal King Arms M4 for $350 through ASC retailers, or any of the other numerous high-quality, non-cansoft AEGs that are now dropping near the $300 range. By the time you're ready to do that, the price point for high end stuff will have likely dropped by a bit and there will be absolutely no reason for you or anyone else to ever buy a low-end un-branded cansoft AEG at Cabelas again.
Hope that helps