Hello,
I agree with the 12V.
No, I have never designed a boost convertor 
I know the principle of operation, and anyhow, I would be most likely using an IC that does the heavy lifting.
But I do know that component selection, placement and ground plate design are important in this domain. But that I don't know enough about it!
I was looking at using a MT3608. They are dirt cheap (around 0.08$ on jlcpcb).
But I just know enough to know that I am unlikely to get it "right" without any help.
I have updated my project (visible at: mini-elt - EasyEDA open source hardware lab ) with a first draft of my design.
But I have no clue if it's correct or not or more accurately how incorrect it is...
My diode and self selection are also things that I have no clue about.
From then on, the PCB design itself is even more iffy!
I would live for anyone to take a look and comment/provide feed back, tell me how to correct it.
Thanks,
Cyrille