I'd also highly recommend the Programming Languages course on Coursera - really changed the way I looked at stuff and made it much easier to learn new programming languages:
I did find it hard to stay the course with MOOCs without additional structure, so I subsequently tried to go to uni and learn this stuff 'properly'. Was pretty saddened then when the place I chose turned out to be not nearly as good as the stuff I could get for free online. 🤦♂️