There are to many variables to get a good answer on that, The type of motorcycle you want plays a big roll in the size of engine. If you are looking at street bikes and you have no experience I would suggest starting with a smaller bike like a 250cc. If you are a experienced rider which I am thinking you are not then it just depends on what you are comfortable with and the style of bike you want. You can always trade up later so most the time I suggest buying used (read cheap) at first until you are sure it is something you will enjoy and get your moneys worth before buying a expensive bike. To many people buy a motorcycle thinking they will love it then end up selling it for a loss later when they realize they don't ride it very often.
Well, it depends on what state you are in, but if you have your motorcycle license, there is no limit to how many cc bike you can have.
A 200 cc motorcycle should do around 75 mph.
150cc
Please check the motorcycle manual to clarify this (related link).
49 Anything 50ccs and over requires a motorcycle endorsement.
Motorcycle
In motorcycle engines, "cc" refers to the total volume of its engine displacement in cubic centimeters.
Yes
Most anti-freeze should be acceptable for a motorcycle. Unless it states on the container not to use it in a motorcycle or not to use it with aluminum, it should be fine in your bike.
49 cc
2377cc
well if your 14 it has 2 be 150cc but you can get by with a 250cc