Welp, here it goes, this will probably take a couple of days and a lot of stress lol but the idea of modeling my own room sounds great.
I'll leave this thread here so I don't need to make 50 threads if I need to ask for help multiple times, also to post my progress I guess, I hope that's alright
So here's my first question, should I actually measure up my room and make my initial plane the same size in meters? Guess that's probably good practice
That is indeed good practice; when possible, always use real-world sizes.
Point 3 in: https://cgcookie.com/articles/6-principles-of-great-3d-modeling