Does it matter which country I am in to pursue this dive?

The best news about studying Chinese Mandarin is that no matter where you are in the world, you can improve your Chinese Mandarin. If you are near a city with a Chinese restaurant, you'll be surprised how excited any native Chinese who work there will be to chat with you in their native language. You can also find practice groups online.

Bottom line, the answer is no: it doesn't matter at all which country you are in. Wherever you are, you can start learning or improve your Chinese Mandarin. Truly, these days, if you want to become fluent in Chinese Mandarin, and you aren't currently fluent, the only reason is: "YOU ARE LAZY". Remember the Break Diver's Creed: No Rules. No Excuses. No Regrets.