I think that you should decide by watching what you want to do after and with this language. It depends the interests, if you are motivated, you will learn any language. You must feel it! It's sure that the languages similar to Chinese probably won't be difficult for you. But it can't determinate us. In this case I should choose Ukrainian, Slovak etc.
You choose by heart ad by your future.
In any case you will find help here
When you choose the language you can ask the useful resources on the forum of this language, the moderators are au courant
Good luck!