Hi, I think you can choose a language you are more interested in learning. If you wanna learn Japanese, just learn it. As a Chinese speaker, I can share some features between Chinese and Japanese. But it will be basic in a view of Chinese speaking learners to learn Japanese. Chinese has tones and you need to remember Chinese characters when you learn new words. That means you need to know how to pronounce a word in speaking and recognize it in reading. While Japanese primarily uses hiragana and katakana scripts in writing. However, since Japanese also uses lots of Chinese characters in writing, it might be helpful. For example, I remember sometimes when my Japanese friends and I meet troubles in communicating, they will try to write Chinese characters for me to see if I can understand. It's a bit like Spanish and Portuguese. The words are similar so you can probably understand. But the grammars of Chinese and Japanese are totally different. :)