Noob taking on big project

Hello im new to programming in general and i want to tackle on some bigger programming, i know some basics however i don't exactly know if i do know them all
but one project i want to work on is slowling building an operating system.

What i want to do:
1.Create a profile make, so a person can make accounts to share a computer
2.Easy program access for people who don't know much about computercraft
3. a way to Hook it up to a server to create fun LAN programs and games

Now also some things i want to do im not sure if possible, but i was working on creating it in the form of an AI, as in anything said sounds abit more human and contains '(Name):' before it all
ex: Jeeves: Hello Sir, Thank you for logging in
i was wondering if there is a way i can randomize what he says to certain phrases, such as i say 'hi' and he will either say "Hellow" or "Hey there" such like that, and if possible a way for when your making an account, you can change his name.

Im not asking anyone to code this form me or any of the like, im wondering 1: The possibility and 2: a push in the general direction to learn how to do all this.

read online on how AI works
ReadTheFuckingManual
look at other peoples Oses (redworks is a good one)
???
profit!!!!

all these things are possible

To start off with the beginning, making a profile. There are allot of examples out there for a password protected computer. Take one of those examples and just add more users/passwords to it, if you want to make it possible for users to add their own profile and save their own data, you should be thinking about databases. You can make it as complex or as simple as you want.

The 2nd question is all in your hands, like pixeltoast says it is good to look at other peoples Os's and think what you would like to improve/ do different with it.

The 3th question is a bit harder to solve. It is possible to make a network within the minecraft computercraft world. Look into rednet API (http://computercraft.info/wiki/index.php?title=Rednet_%28API%29)

Now my ideas about what you want: I think your idea sounds still verry vague. The AI idea is a fun way for users to interact with an OS, but it's the sprinkles on your OS-cake. The question is: how are you going to make the cake? I would answer: from the bottom up. I wouldn't start with the sprinkles, i would start with a solid/smooth sponge base, put jelly in between the sponge, glace the top…. and then we can put sprinkles on the top, or candles, or whatever you want.

Just start by building programs that are handy for you to use in minecraft and start expanding on them. You'll end up with cupcakes, but they do work.
Afterwards you can think about making cakes as big as you like.