Try EdX or Coursera platforms. There is plenty of courses about Artificial Intelligence including machine learning and neural networks. You can get this courses from best universities and making quizzes and projects will advance you. And note that Python is the most common programming language used in ML and NN. So i suggest you learn Python well.
If you want to learn about NN you can start with that site (http://neuralnetworksanddeeplearning.com/chap1.html). It goes step by step and explain all logic behind scene. In my opinion it is the best to enter ML world.
I hope this helps you.