Hey Trash welcome aboard! Check out the Mega ma-10 matched upper/lower sets...they cost a bit more,but you get what you pay for....the small stuff is already installed...which will really help a first time builder, and their uppers/lowers are great quality.
If you can chew gum and walk at the same time you wont have any problems....its when folks go for the pieces that might not be ready for prime time get into trouble... its no fun to spend money on a rifle...put it together,,,then find out it doesnt work right and spend a lot of time trying to find the problem...thats when you have to spit out the gum! :) Wash