Welcome to the Forum FTA -
Someone with no previous knowledge can ABSOLUTELY build an AR from the ground up. We have several members here who have done exactly that.
My young padwan, junho, is a college kid who came to the site in your exact state. Here
is his build thread that he did by himself, and the parts he used, the questions he asked and what he ended up with.
I am a HUGE proponent of building your own weapon over buying one complete for several reasons.
First, you get to decide on the quality of the parts you want, so you can choose what parts you want, not what parts come with the package.
Second, with the knowledge gained by putting it together, you can take it apart, you can inspect it, you can clean it correctly and you can maintain it.
So many people throw some cash at a weapon and expect it to be the solution by itself. Which is great if you work in a gun shop like I do ( part time ) we get orders for complete guns all the time. But how many people really get into the inner workings of their weapon and KNOW how it works? Probably a lot less than you would like to believe.
Now, conversely, I could throw a box of parts on the table in front of junho and tell him to assemble me a working AR, which he could do. He can also self diagnose a problem, and as you can read, make changes to his weapon based on what HE wants to do to it.
Many people have done it & you can too.
The guys here are all willing to help and they would all like to see another AR in a good home.