I used Black Magic MFT at the beginning all the way until i say CUT then we use C100
If you're a beginner I recommend a t3i, (not even a t5i), with a lens that's very fast like F1.4 or T1.6, it will teach you all the basics and give you a foundation in camera operation then from there start playing with lighting and that'll make you better versed in cinematography.
The T3i is quite ideal as it's the tricycle of the camera world, very easy to understand and teaches you the basics; a down scaled version of what you'll encounter with bigger more complex bikes.
But honestly, if you want to be a filmmaker I recommend getting an editing system first, before anything gear wise. I say this with experience, editing is where you really learn what making a film is like.
Also, if you do consider yourself a rookie, don't jump the gun and get something crazy expensive. You must first work with a hammer before you appreciate the drill. If you can make gold out of your t3i and feel that you've pushed that thing to its limits and can operate that camera with your eyes closed, only then are you ready for the drill.
Trust me, there's real value in getting really good with very little, and I believe Scorsese would agree.
P.S. I'd recommend using a film camera every now and then, Analog is an experience. The fact that it's all manual will teach you a lot.