Although java seems to be a good fit for you. It is a cumbersome language to get started out. It will be far easier for you to learn Python and stick with it long term. This is due to the fact you will be easily able to google things for python and you will spend less time learning the language, and more time using it to do what you want.
Making mobile apps is easier with Java due to the fact that google does not directly support app building with python. If this is your biggest priority stick with Java.
Javascript: This language is the best language to learn if you are making a website. However, for easy of use you can do all the database access stuff with python. And send back the data to your website. Javascript is also another cumbersome language in my opinion.
Each language has its use. If I were In your situation, I would choose the language that's easy to start with.