Such opportunities do exist. This discussion board, Cruiser Log can be a great resource in answering your questions. If you have not discovered them yet, we have dedicated forums for various topics, including a Crew Wanted, and Wanting to Crew forums where you can find a position on a cruising yacht.
There is nothing wrong with inexperience, everybody starts that way. Up front honesty, willingness to learn, listen, and help (pitch in and do what needs doing when it needs it) are good traits skippers desire. As you described yourself that should not be a problem. Further with your travel experience, you probably are use to living out of a backpack or a duffle bag; that is another good thing.
Most cruisers sail downhill, meaning they generally try to follow the easiest routes offered by the trade winds, and ocean currents, allowing for tropical storm seasons. Roughly, they do that by staying out of the summer season, changing to the other side of the equator. That could affect the direction and sequence of your agenda. On the other hand there are some that circumnavigate the globe backwards, the hard way, or uphill. In either case, most cruisers are not in a big hurry or a fixed schedule, making allowances for weather.
Start reading the forums, and asking questions. There is a Search feature at the top right of the screen. More members will be along with advice, and answers.
Thanks for logging on, and introducing yourself.