As far as sticks, brands do their own measurements which is pretty stupid. The "standard" way to measure (if youre talking to other goalies) is from heel to paddle, measured like this:
It's going to be all a preference thing, but the paddle length changes where your blocker is. These days, the position of your blocker and stick while in the butterfly matters a lot more than when in your stance (though plenty of people will argue that I'm sure). I'm 5'8 and use a 26" Warrior, which I think is more like 27.5 actual inches (I don't have it in front of me so I can't remember). Or, at least i did until I started cutting a custom grip shape into my paddle - now I use a CCM 27 which is about the equivalent of a 26 after I cut my grip. You can ignore all that, though.
I also started cutting off a couple inches from the shaft just because I find stickhandling easier, but again that's not something you should worry about yet.
As far as type of stick, I still think foam core sticks (thin wood paddle filled with a lightweight foam, usually with a wood shaft) are still by far the best feeling as far as pucks hitting them, and there was a point where composite sticks were more expensive than their performance warrants but nowadays you can get composite for under $100 so that's the route I'd go if I was you. Avoid wood sticks - they're cheap but good god they are HEAVY.
Just like me starting out with pads with leather straps so I don't know any different, which meant I didn't need to get used to something different, I would do the same with sticks if I were you. Start with a composite just so that's all you know. That's the future going forward anyway.