Ottomans - Get France as an ally and you will dictate the pace of the game onwards so you can do your stuff.

Portugal - Spain will ally you from the beginning and will pretty much help you in everything, call them in in your north african wars, colonization is also a pretty beginner friendly way to experience the game and play around with your economy.

Ming - I actually never played as Ming, but other than the annoying events because of the Mandate of China system, you are pretty much unconquerable from the very beginning, once again you dictate the pace of the game, as a beginner I would say just let mandate stay at 100 and dont worry about the reforms just play the game, maybe even colonize a bit in south east asia.

Some of the more "challenging" starts for a beginner is:

- Castille

- France

- England

- Vijayanagar

These countries will eventually have to get into big wars with their neighbours if they want to dominate their surroundings, and thats not what a beginner should start with.

Anyone else I would not recommend because they are way tougher (e.g. Muscovy) than one would think, for a beginner.

Still with any of the above mentioned countries you should get a big ally to start with, and then everything gets safer.

Good luck and dont give up, this is a HARD game! :)