to share some of my experience. i am a newbie too... before i buy my first camera (the only cameras i have prior to having a dslr is phone camera)... i did some much research, ask so much questions...
at that time my only intention is to shoot nightscenary and nothing else...
one fren told me i need tripod, cos i will have to use long exposure... and he said any dslr can do the job, no need for hi iso.
then one fren told me i need hi iso..
another told me i need fast lens...
now i realise , for me, i need all 3... which means a full frame is in fact better, bcos its hi iso performace is better (actually nikon ff performs the best in hi iso)...
in short, it is hard to know what u will need before u try it out. that's my experience.. it may not be yours...
so i feel it is good try with a low cost camera and simple lens.. and as u go, u will know what u need...
now i am shooting more than just nightscenary... so the point i am driving is, once u got the tool, u might use it more than u can imagine in the first place...
that's my experience... it may not be true for others... hope this helps, if not, just discard it.